[syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    cd7a5651db26 alpha: add missing address argument in call t..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1103415a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6d9e410399043c26
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6546859ef2b7/disk-cd7a5651.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f2e4c96e79f7/vmlinux-cd7a5651.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7e21013889c0/bzImage-cd7a5651.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ae466a728017ec940b41@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in dvb_frontend_release+0x40a/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2916
Read of size 4 at addr ffff88802b33a43c by task syz.0.10208/29088

CPU: 1 UID: 0 PID: 29088 Comm: syz.0.10208 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 dvb_frontend_release+0x40a/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2916
 __fput+0x44f/0xa70 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x69b/0x2310 kernel/exit.c:971
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
 get_signal+0x1284/0x1330 kernel/signal.c:3034
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0a9c79bc0b
Code: Unable to access opcode bytes at 0x7f0a9c79bbe1.
RSP: 002b:00007f0a9d607f00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffffc RBX: 0000000000000006 RCX: 00007f0a9c79bc0b
RDX: 00007f0a9d608fd0 RSI: 0000000080085502 RDI: 0000000000000006
RBP: 00007f0a9d608fd0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502
R13: 0000000800000000 R14: 0000000000000000 R15: 00007f0a9c85076a
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5297
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475
 dvb_register_frontend+0x649/0x950 drivers/media/dvb-core/dvb_frontend.c:3051
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
 vidtv_bridge_probe+0x9aa/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0xf9/0x190 drivers/base/platform.c:1446
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:661
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833
 __driver_attach+0x3e7/0x710 drivers/base/dd.c:1227
 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383
 bus_add_driver+0x345/0x670 drivers/base/bus.c:715
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x250/0x840 init/main.c:1382
 do_initcall_level+0x104/0x190 init/main.c:1444
 do_initcalls+0x59/0xa0 init/main.c:1460
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
 kernel_init+0x1d/0x1d0 init/main.c:1582
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 29088:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2670 [inline]
 slab_free mm/slub.c:6082 [inline]
 kfree+0x1c1/0x610 mm/slub.c:6399
 dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline]
 kref_put include/linux/kref.h:65 [inline]
 dvb_device_put drivers/media/dvb-core/dvbdev.c:632 [inline]
 dvb_generic_release+0x11d/0x1b0 drivers/media/dvb-core/dvbdev.c:169
 dvb_frontend_release+0x132/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2914
 __fput+0x44f/0xa70 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x69b/0x2310 kernel/exit.c:971
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
 get_signal+0x1284/0x1330 kernel/signal.c:3034
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802b33a400
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 60 bytes inside of
 freed 256-byte region [ffff88802b33a400, ffff88802b33a500)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b33a
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813fe9db40 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe9db40 dead000000000122 0000000000000000
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0000acce81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 13065394638, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1883
 prep_new_page mm/page_alloc.c:1891 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3956
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5244
 alloc_slab_page mm/slub.c:3238 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3411
 new_slab mm/slub.c:3469 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7091
 refill_sheaf mm/slub.c:2787 [inline]
 __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4536
 alloc_from_pcs mm/slub.c:4639 [inline]
 slab_alloc_node mm/slub.c:4773 [inline]
 __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5292
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 bus_add_driver+0x162/0x670 drivers/base/bus.c:699
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078
 do_one_initcall+0x250/0x840 init/main.c:1382
 do_initcall_level+0x104/0x190 init/main.c:1444
 do_initcalls+0x59/0xa0 init/main.c:1460
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
 kernel_init+0x1d/0x1d0 init/main.c:1582
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802b33a300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b33a380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b33a400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88802b33a480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b33a500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bcf6e6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ce3652580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1121515a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b33c549157ca/disk-c22e26bd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/34c7ded19553/vmlinux-c22e26bd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/66faec2158ed/bzImage-c22e26bd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ae466a728017ec940b41@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in dvb_frontend_release+0x410/0x4e0 drivers/media/dvb-core/dvb_frontend.c:2916
Read of size 4 at addr ffff88802b75b83c by task syz.0.18/5958

CPU: 1 UID: 0 PID: 5958 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 dvb_frontend_release+0x410/0x4e0 drivers/media/dvb-core/dvb_frontend.c:2916
 __fput+0x45e/0xa80 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 get_signal+0x11c3/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc97690bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffed13b68c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffed13b69b0 RCX: 00007fc97690bf79
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000195a3 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2d420000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc976b85fac R14: 00007fc976b85fa8 R15: 00007fc976b85fa0
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5297
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475
 dvb_register_frontend+0x665/0x970 drivers/media/dvb-core/dvb_frontend.c:3051
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
 vidtv_bridge_probe+0x9aa/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0xf9/0x190 drivers/base/platform.c:1446
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:661
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833
 __driver_attach+0x349/0x640 drivers/base/dd.c:1227
 bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383
 bus_add_driver+0x348/0x670 drivers/base/bus.c:715
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x250/0x840 init/main.c:1378
 do_initcall_level+0x104/0x190 init/main.c:1440
 do_initcalls+0x59/0xa0 init/main.c:1456
 kernel_init_freeable+0x2a6/0x3d0 init/main.c:1688
 kernel_init+0x1d/0x1d0 init/main.c:1578
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5958:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2670 [inline]
 slab_free mm/slub.c:6082 [inline]
 kfree+0x1c1/0x690 mm/slub.c:6399
 dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline]
 kref_put include/linux/kref.h:65 [inline]
 dvb_device_put drivers/media/dvb-core/dvbdev.c:632 [inline]
 dvb_generic_release+0x123/0x1c0 drivers/media/dvb-core/dvbdev.c:169
 dvb_frontend_release+0x138/0x4e0 drivers/media/dvb-core/dvb_frontend.c:2914
 __fput+0x45e/0xa80 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 get_signal+0x11c3/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802b75b800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 60 bytes inside of
 freed 512-byte region [ffff88802b75b800, ffff88802b75ba00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b758
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe0dc80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe0dc80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000002 ffffea0000add601 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2, tgid 2 (kthreadd), ts 14639760172, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3950
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5245
 alloc_slab_page mm/slub.c:3238 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3411
 new_slab mm/slub.c:3469 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7091
 refill_sheaf mm/slub.c:2787 [inline]
 __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4536
 alloc_from_pcs mm/slub.c:4639 [inline]
 slab_alloc_node mm/slub.c:4773 [inline]
 __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5292
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 set_kthread_struct+0xbb/0x340 kernel/kthread.c:125
 copy_process+0x128c/0x3d00 kernel/fork.c:2152
 kernel_clone+0x249/0x7f0 kernel/fork.c:2654
 kernel_thread+0x13f/0x1b0 kernel/fork.c:2715
 create_kthread kernel/kthread.c:490 [inline]
 kthreadd+0x4ec/0x6e0 kernel/kthread.c:849
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802b75b700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b75b780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b75b800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88802b75b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b75b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Forwarded: KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: KASAN: slab-use-after-free Read in dvb_frontend_release (3)
Author: ttt978615@gmail.com

#syz test upstream c22e26bd0906e9c8325462993f01adb16b8ea2c0

--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -2911,6 +2911,7 @@ static int dvb_frontend_release(struct inode *inode,
struct file *file)
                mb();
        }

+       dvb_device_get(dvbdev);
        ret = dvb_generic_release(inode, file);

        if (dvbdev->users == -1) {
@@ -2931,6 +2932,7 @@ static int dvb_frontend_release(struct inode *inode,
struct file *file)
                        fe->ops.ts_bus_ctrl(fe, 0);
        }

+       dvb_device_put(dvbdev);
        dvb_frontend_put(fe);

        return ret;

Forwarded: KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: KASAN: slab-use-after-free Read in dvb_frontend_release (3)
Author: ttt978615@gmail.com

#syz test upstream c22e26bd0906e9c8325462993f01adb16b8ea2c0

Forwarded: KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: KASAN: slab-use-after-free Read in dvb_frontend_release (3)
Author: ttt978615@gmail.com

#syz test upstream c22e26bd0906e9c8325462993f01adb16b8ea2c0

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[Hillf Danton]

> Date: Mon, 16 Feb 2026 01:34:34 -0800	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16bcf6e6580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e
> dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ce3652580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1121515a580000

#syz test

--- x/drivers/media/dvb-core/dvb_frontend.c
+++ y/drivers/media/dvb-core/dvb_frontend.c
@@ -2911,6 +2911,7 @@ static int dvb_frontend_release(struct i
 		mb();
 	}
 
+	dvb_device_get(dvbdev);
 	ret = dvb_generic_release(inode, file);
 
 	if (dvbdev->users == -1) {
@@ -2930,6 +2931,7 @@ static int dvb_frontend_release(struct i
 		if (fe->ops.ts_bus_ctrl)
 			fe->ops.ts_bus_ctrl(fe, 0);
 	}
+	dvb_device_put(dvbdev);
 
 	dvb_frontend_put(fe);
 
--

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in dvb_device_open

==================================================================
BUG: KASAN: slab-use-after-free in dvb_device_open+0xc4/0x360 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff88802b6da418 by task syz.0.19/6637

CPU: 1 UID: 0 PID: 6637 Comm: syz.0.19 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 dvb_device_open+0xc4/0x360 drivers/media/dvb-core/dvbdev.c:99
 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:411
 do_dentry_open+0x83d/0x13e0 fs/open.c:949
 vfs_open+0x3b/0x350 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e43/0x38a0 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0b55cdc84e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f0b5537db28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0b5537e6c0 RCX: 00007f0b55cdc84e
RDX: 0000000000000400 RSI: 00007f0b5537dc00 RDI: ffffffffffffff9c
RBP: 00007f0b5537dc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f0b55f96038 R14: 00007f0b55f95fa0 R15: 00007ffc62e6c1b8
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5339
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475
 dvb_register_frontend+0x665/0x970 drivers/media/dvb-core/dvb_frontend.c:3053
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
 vidtv_bridge_probe+0x9aa/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0xf9/0x190 drivers/base/platform.c:1446
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:661
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833
 __driver_attach+0x3e7/0x710 drivers/base/dd.c:1227
 bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383
 bus_add_driver+0x348/0x670 drivers/base/bus.c:715
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x250/0x8d0 init/main.c:1382
 do_initcall_level+0x104/0x190 init/main.c:1444
 do_initcalls+0x59/0xa0 init/main.c:1460
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
 kernel_init+0x1d/0x1d0 init/main.c:1582
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 6634:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kfree+0x1c1/0x6c0 mm/slub.c:6442
 dvb_frontend_release+0x3de/0x500 drivers/media/dvb-core/dvb_frontend.c:2934
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802b6da400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 freed 512-byte region [ffff88802b6da400, ffff88802b6da600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b6d8
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe1cc80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe1cc80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000002 ffffea0000adb601 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 13477098013, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4578
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5334
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 bus_add_driver+0x165/0x670 drivers/base/bus.c:699
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078
 do_one_initcall+0x250/0x8d0 init/main.c:1382
 do_initcall_level+0x104/0x190 init/main.c:1444
 do_initcalls+0x59/0xa0 init/main.c:1460
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
 kernel_init+0x1d/0x1d0 init/main.c:1582
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802b6da300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b6da380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b6da400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88802b6da480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b6da500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         d79526b8 Merge tag 'spi-fix-v7.0-merge-window' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14195722580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4b084d82ac8e0fbd
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=178a0006580000

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[Hillf Danton]

> Date: Mon, 16 Feb 2026 01:34:34 -0800	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16bcf6e6580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e
> dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ce3652580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1121515a580000

#syz test

--- x/drivers/media/dvb-core/dvb_frontend.c
+++ y/drivers/media/dvb-core/dvb_frontend.c
@@ -2911,6 +2911,8 @@ static int dvb_frontend_release(struct i
 		mb();
 	}
 
+	dvb_device_get(dvbdev); // for removing dev
+	dvb_device_get(dvbdev); // for releasing dev
 	ret = dvb_generic_release(inode, file);
 
 	if (dvbdev->users == -1) {
@@ -2931,6 +2933,8 @@ static int dvb_frontend_release(struct i
 			fe->ops.ts_bus_ctrl(fe, 0);
 	}
 
+	dvb_remove_device(dvbdev);
+	dvb_device_put(dvbdev);
 	dvb_frontend_put(fe);
 
 	return ret;
--

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: corrupted list in dvb_remove_device

 non-paged memory
list_del corruption, ffff88802b938400->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:58!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 6584 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__list_del_entry_valid_or_report+0x10e/0x190 lib/list_debug.c:56
Code: a0 47 a6 8b 48 89 de e8 20 01 80 fc 90 0f 0b 4c 89 e7 e8 b5 c4 61 fd 48 c7 c7 00 48 a6 8b 48 89 de 4c 89 e2 e8 03 01 80 fc 90 <0f> 0b 4c 89 e7 e8 98 c4 61 fd 48 c7 c7 60 48 a6 8b 48 89 de 4c 89
RSP: 0018:ffffc90003b6fa88 EFLAGS: 00010246
RAX: 000000000000004e RBX: ffff88802b938400 RCX: 70c5d03fc278f600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1017124923 R12: dead000000000100
R13: dffffc0000000000 R14: dead000000000100 R15: dead000000000122
FS:  000055556ef5d500(0000) GS:ffff888126442000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f467ca4efeb CR3: 0000000025052000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:132 [inline]
 __list_del_entry include/linux/list.h:223 [inline]
 list_del include/linux/list.h:237 [inline]
 dvb_remove_device+0x131/0x280 drivers/media/dvb-core/dvbdev.c:611
 dvb_frontend_release+0x3e6/0x510 drivers/media/dvb-core/dvb_frontend.c:2936
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 get_signal+0x11c3/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe67637bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc7f8caa78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc7f8cab60 RCX: 00007fe67637bf79
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000023360 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b30020000 R11: 0000000000000246 R12: 00007ffc7f8caba0
R13: 00007fe6765f5fac R14: 00000000000233c3 R15: 00007fe6765f5fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x10e/0x190 lib/list_debug.c:56
Code: a0 47 a6 8b 48 89 de e8 20 01 80 fc 90 0f 0b 4c 89 e7 e8 b5 c4 61 fd 48 c7 c7 00 48 a6 8b 48 89 de 4c 89 e2 e8 03 01 80 fc 90 <0f> 0b 4c 89 e7 e8 98 c4 61 fd 48 c7 c7 60 48 a6 8b 48 89 de 4c 89
RSP: 0018:ffffc90003b6fa88 EFLAGS: 00010246
RAX: 000000000000004e RBX: ffff88802b938400 RCX: 70c5d03fc278f600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1017124923 R12: dead000000000100
R13: dffffc0000000000 R14: dead000000000100 R15: dead000000000122
FS:  000055556ef5d500(0000) GS:ffff888126442000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f467ca4efeb CR3: 0000000025052000 CR4: 00000000003526f0


Tested on:

commit:         d79526b8 Merge tag 'spi-fix-v7.0-merge-window' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=143a8152580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4b084d82ac8e0fbd
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1572f95a580000

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[Hillf Danton]

> Date: Mon, 16 Feb 2026 01:34:34 -0800	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16bcf6e6580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e
> dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ce3652580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1121515a580000

#syz test

--- x/drivers/media/dvb-core/dvb_frontend.c
+++ y/drivers/media/dvb-core/dvb_frontend.c
@@ -2836,6 +2836,7 @@ static int dvb_frontend_open(struct inod
 
 	if ((ret = dvb_generic_open(inode, file)) < 0)
 		goto err1;
+	dvb_device_get(dvbdev);
 
 	if ((file->f_flags & O_ACCMODE) != O_RDONLY) {
 		/* normal tune mode when opened R/W */
--

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level)
[    0.324084][    T0] ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level)
[    0.324103][    T0] ACPI: Using ACPI (MADT) for SMP configuration information
[    0.324118][    T0] CPU topo: Max. logical packages:   1
[    0.324122][    T0] CPU topo: Max. logical dies:       1
[    0.324126][    T0] CPU topo: Max. dies per package:   1
[    0.324137][    T0] CPU topo: Max. threads per core:   2
[    0.324142][    T0] CPU topo: Num. cores per package:     1
[    0.324146][    T0] CPU topo: Num. threads per package:   2
[    0.324150][    T0] CPU topo: Allowing 2 present CPUs plus 0 hotplug CPUs
[    0.324260][    T0] PM: hibernation: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.324270][    T0] PM: hibernation: Registered nosave memory: [mem 0x0009f000-0x000fffff]
[    0.324278][    T0] PM: hibernation: Registered nosave memory: [mem 0xbfffd000-0xffffffff]
[    0.324303][    T0] [gap 0xc0000000-0xfffbbfff] available for PCI devices
[    0.324309][    T0] Booting paravirtualized kernel on KVM
[    0.324320][    T0] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.457957][    T0] Zone ranges:
[    0.457966][    T0]   DMA      [mem 0x0000000000001000-0x0000000000ffffff]
[    0.457977][    T0]   DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
[    0.457985][    T0]   Normal   [mem 0x0000000100000000-0x000000023fffffff]
[    0.457993][    T0]   Device   empty
[    0.457998][    T0] Movable zone start for each node
[    0.458001][    T0] Early memory node ranges
[    0.458005][    T0]   node   0: [mem 0x0000000000001000-0x000000000009efff]
[    0.458011][    T0]   node   0: [mem 0x0000000000100000-0x00000000bfffcfff]
[    0.458019][    T0]   node   0: [mem 0x0000000100000000-0x0000000140000fff]
[    0.458025][    T0]   node   1: [mem 0x0000000140001000-0x000000023fffffff]
[    0.458034][    T0] Initmem setup node 0 [mem 0x0000000000001000-0x0000000140000fff]
[    0.458049][    T0] Initmem setup node 1 [mem 0x0000000140001000-0x000000023fffffff]
[    0.458095][    T0] On node 0, zone DMA: 1 pages in unavailable ranges
[    0.458339][    T0] On node 0, zone DMA: 97 pages in unavailable ranges
[    0.520754][    T0] On node 0, zone Normal: 3 pages in unavailable ranges
[    0.583334][    T0] setup_percpu: NR_CPUS:8 nr_cpumask_bits:2 nr_cpu_ids:2 nr_node_ids:2
[    0.584030][    T0] percpu: Embedded 72 pages/cpu s254408 r8192 d32312 u1048576
[    0.584054][    T0] pcpu-alloc: s254408 r8192 d32312 u1048576 alloc=1*2097152
[    0.584066][    T0] pcpu-alloc: [0] 0 1 
[    0.584177][    T0] kvm-guest: PV spinlocks enabled
[    0.584186][    T0] PV qspinlock hash table entries: 256 (order: 0, 4096 bytes, linear)
[    0.584203][    T0] Kernel command line: earlyprintk=serial net.ifnames=0 sysctl.kernel.hung_task_all_cpu_backtrace=1 ima_policy=tcb nf-conntrack-ftp.ports=20000 nf-conntrack-tftp.ports=20000 nf-conntrack-sip.ports=20000 nf-conntrack-irc.ports=20000 nf-conntrack-sane.ports=20000 binder.debug_mask=0 rcupdate.rcu_expedited=1 rcupdate.rcu_cpu_stall_cputime=1 no_hash_pointers page_owner=on sysctl.vm.nr_hugepages=4 sysctl.vm.nr_overcommit_hugepages=4 secretmem.enable=1 sysctl.max_rcu_stall_to_panic=1 msr.allow_writes=off coredump_filter=0xffff root=/dev/sda console=ttyS0 vsyscall=native numa=fake=2 kvm-intel.nested=1 spec_store_bypass_disable=prctl nopcid vivid.n_devs=64 vivid.multiplanar=1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2 netrom.nr_ndevs=32 rose.rose_ndevs=32 smp.csd_lock_timeout=100000 watchdog_thresh=55 workqueue.watchdog_thresh=140 sysctl.net.core.netdev_unregister_timeout_secs=140 dummy_hcd.num=32 max_loop=32 nbds_max=32 \
[    0.584229][    T0] Kernel command line: comedi.comedi_num_legacy_minors=4 panic_on_warn=1 BOOT_IMAGE=/boot/bzImage root=/dev/sda1 console=ttyS0
[    0.588483][    T0] Unknown kernel command line parameters "nbds_max=32", will be passed to user space.
[    0.588544][    T0] random: crng init done
[    0.588547][    T0] printk: log buffer data + meta data: 262144 + 917504 = 1179648 bytes
[    0.588761][    T0] software IO TLB: area num 2.
[    0.616645][    T0] Fallback order for Node 0: 0 1 
[    0.616664][    T0] Fallback order for Node 1: 1 0 
[    0.616678][    T0] Built 2 zonelists, mobility grouping on.  Total pages: 2097051
[    0.616685][    T0] Policy zone: Normal
[    0.617377][    T0] mem auto-init: stack:all(zero), heap alloc:on, heap free:off
[    0.617385][    T0] stackdepot: allocating hash table via alloc_large_system_hash
[    0.617395][    T0] stackdepot hash table entries: 1048576 (order: 12, 16777216 bytes, linear)
[    0.622068][    T0] stackdepot: allocating space for 8192 stack pools via memblock
[    1.210344][    T0] **********************************************************
[    1.210354][    T0] **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
[    1.210358][    T0] **                                                      **
[    1.210362][    T0] ** This system shows unhashed kernel memory addresses   **
[    1.210365][    T0] ** via the console, logs, and other interfaces. This    **
[    1.210369][    T0] ** might reduce the security of your system.            **
[    1.210373][    T0] **                                                      **
[    1.210376][    T0] ** If you see this message and you are not debugging    **
[    1.210380][    T0] ** the kernel, report this immediately to your system   **
[    1.210384][    T0] ** administrator!                                       **
[    1.210387][    T0] **                                                      **
[    1.210391][    T0] ** Use hash_pointers=always to force this mode off      **
[    1.210395][    T0] **                                                      **
[    1.210398][    T0] **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
[    1.210402][    T0] **********************************************************
[    1.213877][    T0] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=2
[    1.344641][    T0] allocated 167772160 bytes of page_ext
[    1.344682][    T0] Node 0, zone      DMA: page owner found early allocated 0 pages
[    1.358368][    T0] Node 0, zone    DMA32: page owner found early allocated 21120 pages
[    1.362689][    T0] Node 0, zone   Normal: page owner found early allocated 130 pages
[    1.373648][    T0] Node 1, zone   Normal: page ownserialport: Connected to syzkaller.us-central1-c.ci-upstream-kasan-gce-smack-root-test-job-parallel-0 port 1 (session ID: 27e7da33582c2a1f5960f3e4d1e08a357e0ae697147fe044510b0304e2ed012c, active connections: 1).
er found early allocated 19848 pages
[    1.374121][    T0] Kernel/User page tables isolation: enabled
[    1.376324][    T0] Dynamic Preempt: full
[    1.377426][    T0] ------------[ cut here ]------------
[    1.377431][    T0] overflows_flex_counter_type(typeof(*ctx), pwq_tbl, __count)
[    1.377435][    T0] WARNING: kernel/workqueue.c:5373 at apply_wqattrs_prepare+0xa5/0x1f0, CPU#0: swapper/0/0
[    1.377461][    T0] Modules linked in:
[    1.377470][    T0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
[    1.377481][    T0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
[    1.377488][    T0] RIP: 0010:apply_wqattrs_prepare+0xa5/0x1f0
[    1.377507][    T0] Code: d8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 2b 01 00 00 8b 1b bf 05 00 00 00 89 de e8 55 2b 35 00 83 fb 06 0f 83 ce 00 00 00 90 <0f> 0b 90 48 c7 c0 60 61 5e 8d 48 c1 e8 03 42 80 3c 38 00 74 0c 48
[    1.377516][    T0] RSP: 0000:ffffffff8d807bf8 EFLAGS: 00010097
[    1.377524][    T0] RAX: ffffffff818e73bb RBX: 0000000000000000 RCX: ffffffff8d902f00
[    1.377531][    T0] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
[    1.377537][    T0] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
[    1.377543][    T0] R10: dffffc0000000000 R11: fffffbfff1e912b7 R12: ffff88813fe749c8
[    1.377550][    T0] R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000
[    1.377562][    T0] FS:  0000000000000000(0000) GS:ffff888126592000(0000) knlGS:0000000000000000
[    1.377572][    T0] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.377579][    T0] CR2: ffff88823ffff000 CR3: 000000000d9ba000 CR4: 00000000000000b0
[    1.377588][    T0] Call Trace:
[    1.377593][    T0]  <TASK>
[    1.377599][    T0]  __alloc_workqueue+0xfbe/0x1e70
[    1.377617][    T0]  alloc_workqueue_noprof+0xe3/0x210
[    1.377629][    T0]  ? is_dynamic_key+0xd6/0x1c0
[    1.377644][    T0]  ? __pfx_alloc_workqueue_noprof+0x10/0x10
[    1.377657][    T0]  ? __kmalloc_cache_noprof+0x3a6/0x690
[    1.377670][    T0]  ? workqueue_init_early+0x89b/0xcf0
[    1.377687][    T0]  workqueue_init_early+0xaac/0xcf0
[    1.377700][    T0]  ? __cpuhp_setup_state+0x46/0x60
[    1.377717][    T0]  ? __pfx_workqueue_init_early+0x10/0x10
[    1.377733][    T0]  ? register_trace_event+0x3f7/0x4b0
[    1.377749][    T0]  start_kernel+0x189/0x3d0
[    1.377760][    T0]  x86_64_start_reservations+0x24/0x30
[    1.377773][    T0]  x86_64_start_kernel+0x143/0x1c0
[    1.377786][    T0]  common_startup_64+0x13e/0x147
[    1.377804][    T0]  </TASK>
[    1.377810][    T0] Kernel panic - not syncing: kernel: panic_on_warn set ...
[    1.377816][    T0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
[    1.377827][    T0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
[    1.377833][    T0] Call Trace:
[    1.377837][    T0]  <TASK>
[    1.377840][    T0]  vpanic+0x56c/0xa60
[    1.377856][    T0]  ? __pfx__printk+0x10/0x10
[    1.377868][    T0]  ? __pfx_vpanic+0x10/0x10
[    1.377881][    T0]  ? is_bpf_text_address+0x292/0x2b0
[    1.377894][    T0]  ? is_bpf_text_address+0x26/0x2b0
[    1.377914][    T0]  panic+0xc5/0xd0
[    1.377928][    T0]  ? __pfx_panic+0x10/0x10
[    1.377947][    T0]  ? common_startup_64+0x13e/0x147
[    1.377959][    T0]  __warn+0x315/0x4f0
[    1.377973][    T0]  ? apply_wqattrs_prepare+0xa5/0x1f0
[    1.377987][    T0]  ? apply_wqattrs_prepare+0xa5/0x1f0
[    1.378000][    T0]  __report_bug+0x29a/0x540
[    1.378020][    T0]  ? apply_wqattrs_prepare+0xa5/0x1f0
[    1.378033][    T0]  ? __pfx___report_bug+0x10/0x10
[    1.378049][    T0]  ? do_raw_spin_unlock+0xf6/0x210
[    1.378064][    T0]  ? _raw_spin_unlock_irqrestore+0x4c/0x80
[    1.378074][    T0]  ? rt_mutex_slowunlock+0x1cb/0x300
[    1.378088][    T0]  ? __pfx_rt_mutex_slowunlock+0x10/0x10
[    1.378102][    T0]  ? apply_wqattrs_prepare+0xa5/0x1f0
[    1.378115][    T0]  report_bug+0x16a/0x220
[    1.378130][    T0]  ? apply_wqattrs_prepare+0xa5/0x1f0
[    1.378142][    T0]  ? apply_wqattrs_prepare+0xa7/0x1f0
[    1.378155][    T0]  handle_bug+0x98/0x200
[    1.378168][    T0]  exc_invalid_op+0x1a/0x50
[    1.378179][    T0]  asm_exc_invalid_op+0x1a/0x20
[    1.378190][    T0] RIP: 0010:apply_wqattrs_prepare+0xa5/0x1f0
[    1.378203][    T0] Code: d8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 2b 01 00 00 8b 1b bf 05 00 00 00 89 de e8 55 2b 35 00 83 fb 06 0f 83 ce 00 00 00 90 <0f> 0b 90 48 c7 c0 60 61 5e 8d 48 c1 e8 03 42 80 3c 38 00 74 0c 48
[    1.378211][    T0] RSP: 0000:ffffffff8d807bf8 EFLAGS: 00010097
[    1.378219][    T0] RAX: ffffffff818e73bb RBX: 0000000000000000 RCX: ffffffff8d902f00
[    1.378226][    T0] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
[    1.378231][    T0] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
[    1.378237][    T0] R10: dffffc0000000000 R11: fffffbfff1e912b7 R12: ffff88813fe749c8
[    1.378244][    T0] R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000
[    1.378254][    T0]  ? apply_wqattrs_prepare+0x9b/0x1f0
[    1.378270][    T0]  ? apply_wqattrs_prepare+0x9b/0x1f0
[    1.378284][    T0]  __alloc_workqueue+0xfbe/0x1e70
[    1.378300][    T0]  alloc_workqueue_noprof+0xe3/0x210
[    1.378312][    T0]  ? is_dynamic_key+0xd6/0x1c0
[    1.378326][    T0]  ? __pfx_alloc_workqueue_noprof+0x10/0x10
[    1.378339][    T0]  ? __kmalloc_cache_noprof+0x3a6/0x690
[    1.378351][    T0]  ? workqueue_init_early+0x89b/0xcf0
[    1.378367][    T0]  workqueue_init_early+0xaac/0xcf0
[    1.378380][    T0]  ? __cpuhp_setup_state+0x46/0x60
[    1.378396][    T0]  ? __pfx_workqueue_init_early+0x10/0x10
[    1.378412][    T0]  ? register_trace_event+0x3f7/0x4b0
[    1.378426][    T0]  start_kernel+0x189/0x3d0
[    1.378436][    T0]  x86_64_start_reservations+0x24/0x30
[    1.378449][    T0]  x86_64_start_kernel+0x143/0x1c0
[    1.378462][    T0]  common_startup_64+0x13e/0x147
[    1.378479][    T0]  </TASK>


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build634184225=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs-2/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs-2/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 1e62d19825
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=1e62d1982527c3b4e18df04d61f2560fa1f434cc -X github.com/google/syzkaller/prog.gitRevisionDate=20260213-152336"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=1e62d1982527c3b4e18df04d61f2560fa1f434cc -X github.com/google/syzkaller/prog.gitRevisionDate=20260213-152336"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=1e62d1982527c3b4e18df04d61f2560fa1f434cc -X github.com/google/syzkaller/prog.gitRevisionDate=20260213-152336"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"1e62d1982527c3b4e18df04d61f2560fa1f434cc\"
/usr/bin/ld: /tmp/ccZjc2ZB.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=17938152580000


Tested on:

commit:         8934827d Merge tag 'kmalloc_obj-treewide-v7.0-rc1' of ..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=5ca447d428dc7079
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=114b7c02580000

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[Hillf Danton]

> Date: Mon, 16 Feb 2026 01:34:34 -0800	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16bcf6e6580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e
> dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ce3652580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1121515a580000

#syz test

--- x/drivers/media/dvb-core/dvb_frontend.c
+++ y/drivers/media/dvb-core/dvb_frontend.c
@@ -3072,12 +3072,15 @@ EXPORT_SYMBOL(dvb_register_frontend);
 int dvb_unregister_frontend(struct dvb_frontend *fe)
 {
 	struct dvb_frontend_private *fepriv = fe->frontend_priv;
+	struct dvb_device *dvbdev;
 
 	dev_dbg(fe->dvb->device, "%s:\n", __func__);
 
 	mutex_lock(&frontend_mutex);
 	dvb_frontend_stop(fe);
-	dvb_remove_device(fepriv->dvbdev);
+	dvbdev = fepriv->dvbdev;
+	fepriv->dvbdev = NULL;
+	dvb_unregister_device(dvbdev);
 
 	/* fe is invalid now */
 	mutex_unlock(&frontend_mutex);
--

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in dvb_frontend_release

==================================================================
BUG: KASAN: slab-use-after-free in dvb_frontend_release+0x410/0x4e0 drivers/media/dvb-core/dvb_frontend.c:2916
Read of size 4 at addr ffff88802b9c543c by task syz.0.19/6629

CPU: 1 UID: 0 PID: 6629 Comm: syz.0.19 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engi[  145.718954][ T6629] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 dvb_frontend_release+0x410/0x4e0 drivers/media/dvb-core/dvb_frontend.c:2916
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5097f2bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe9efc5af8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffe9efc5be0 RCX: 00007f5097f2bf79
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000023863 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33620000 R11: 0000000000000246 R12: 00007ffe9efc5c20
R13: 00007f50981a5fac R14: 00000000000238a9 R15: 00007f50981a5fa0
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5339
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1200 [inline]
 dvb_register_device+0x2fd/0x21e0 drivers/media/dvb-core/dvbdev.c:472
 dvb_register_frontend+0x665/0x970 drivers/media/dvb-core/dvb_frontend.c:3051
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
 vidtv_bridge_probe+0x9aa/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0xf9/0x190 drivers/base/platform.c:1446
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:661
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833
 __driver_attach+0x3e7/0x710 drivers/base/dd.c:1227
 bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383
 bus_add_driver+0x348/0x670 drivers/base/bus.c:715
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x250/0x8d0 init/main.c:1382
 do_initcall_level+0x104/0x190 init/main.c:1444
 do_initcalls+0x59/0xa0 init/main.c:1460
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
 kernel_init+0x1d/0x1d0 init/main.c:1582
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 6629:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kfree+0x1c1/0x6c0 mm/slub.c:6442
 dvb_free_device drivers/media/dvb-core/dvbdev.c:616 [inline]
 kref_put include/linux/kref.h:65 [inline]
 dvb_device_put drivers/media/dvb-core/dvbdev.c:629 [inline]
 dvb_generic_release+0x123/0x1c0 drivers/media/dvb-core/dvbdev.c:169
 dvb_frontend_release+0x138/0x4e0 drivers/media/dvb-core/dvb_frontend.c:2914
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802b9c5400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 60 bytes inside of
 freed 512-byte region [ffff88802b9c5400, ffff88802b9c5600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b9c4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe17c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe17c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000002 ffffea0000ae7101 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 13901801393, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4578
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5334
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1200 [inline]
 bus_add_driver+0x165/0x670 drivers/base/bus.c:699
 driver_register+0x23a/0x320 drivers/base/driver.c:249
 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078
 do_one_initcall+0x250/0x8d0 init/main.c:1382
 do_initcall_level+0x104/0x190 init/main.c:1444
 do_initcalls+0x59/0xa0 init/main.c:1460
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
 kernel_init+0x1d/0x1d0 init/main.c:1582
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802b9c5300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b9c5380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b9c5400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88802b9c5480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b9c5500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         32a92f8c Convert more 'alloc_obj' cases to default GFP..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=178a055a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5ca447d428dc7079
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14cadd94580000

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[Hillf Danton]

> Date: Mon, 16 Feb 2026 01:34:34 -0800	[thread overview]
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16bcf6e6580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e
> dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ce3652580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1121515a580000

#syz test

--- x/drivers/media/dvb-core/dvb_frontend.c
+++ y/drivers/media/dvb-core/dvb_frontend.c
@@ -2836,6 +2836,7 @@ static int dvb_frontend_open(struct inod
 
 	if ((ret = dvb_generic_open(inode, file)) < 0)
 		goto err1;
+	dvb_device_get(dvbdev);
 
 	if ((file->f_flags & O_ACCMODE) != O_RDONLY) {
 		/* normal tune mode when opened R/W */
@@ -3077,7 +3078,8 @@ int dvb_unregister_frontend(struct dvb_f
 
 	mutex_lock(&frontend_mutex);
 	dvb_frontend_stop(fe);
-	dvb_remove_device(fepriv->dvbdev);
+	dvb_unregister_device(fepriv->dvbdev);
+	fepriv->dvbdev = NULL;
 
 	/* fe is invalid now */
 	mutex_unlock(&frontend_mutex);
--

Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+ae466a728017ec940b41@syzkaller.appspotmail.com
Tested-by: syzbot+ae466a728017ec940b41@syzkaller.appspotmail.com

Tested on:

commit:         6de23f81 Linux 7.0-rc1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10953722580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4322f17fa28ade5f
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=157cc152580000

Note: testing is done by a robot and is best-effort only.

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Subject: 
Author: halves@igalia.com

#syz test

--- a/drivers/media/dvb-core/dvbdev.c
+++ b/drivers/media/dvb-core/dvbdev.c
@@ -147,6 +147,7 @@ int dvb_generic_open(struct inode *inode, struct file *file)
                dvbdev->writers--;
        }

+       dvb_device_get(dvbdev);
        dvbdev->users--;
        return 0;
 }
-- 
2.53.0

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#syz invalid

Hasn't happened in a long while

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#syz invalid

Hasn't happened for a long while

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#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
58717b2a1365

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#syz test

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Let's check if the command works.

#syz test

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Apparently, already fixed.

#syz invalid

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Hasn't been happening in a long while.

#syz invalid

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#syz invalid

hasn't happened in a while

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#syz invalid

It hasn't been happening in a very long time.

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#syz invalid

Actually already fixed

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#syz invalid

Fixed long ago

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#syz invalid

Actually fixed long ago.

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#syz invalid

Doesn't happen for a long time in fact.

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The bug has actually been already fixed.

#syz invalid

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#syz invalid

The bug is actually no longer present.

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The bug is actually fixed long time ago.

#syz invalid

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#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

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#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 91fd3673c09a..e588a188f50a 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -126,23 +126,10 @@ static enum hrtimer_restart
xen_timer_callback(struct hrtimer *timer)
 {
 	struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu,
 					     arch.xen.timer);
-	struct kvm_xen_evtchn e;
-	int rc;

 	if (atomic_read(&vcpu->arch.xen.timer_pending))
 		return HRTIMER_NORESTART;

-	e.vcpu_id = vcpu->vcpu_id;
-	e.vcpu_idx = vcpu->vcpu_idx;
-	e.port = vcpu->arch.xen.timer_virq;
-	e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
-
-	rc = kvm_xen_set_evtchn_fast(&e, vcpu->kvm);
-	if (rc != -EWOULDBLOCK) {
-		vcpu->arch.xen.timer_expires = 0;
-		return HRTIMER_NORESTART;
-	}
-
 	atomic_inc(&vcpu->arch.xen.timer_pending);
 	kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
 	kvm_vcpu_kick(vcpu);

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#syz test

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#syz invalid

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#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git
4daba9379bbd702c63459f54ef448746bfeab42d

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#syz test

---
 fs/minix/inode.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index 7897f5123b3d..bee191c50010 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -171,7 +171,15 @@ static bool minix_check_superblock(struct super_block *sb)
 {
 	struct minix_sb_info *sbi = minix_sb(sb);
 
-	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
+	if (sbi->s_log_zone_size != 0) {
+		printk("minix-fs error: zone size must equal block size. "
+		       "s_log_zone_size > 0 is not supported.\n");
+		return false;
+	}
+
+	if (sbi->s_imap_blocks < 1 || sbi->s_zmap_blocks < 1 ||
+	    sbi->s_ninodes < 1 || sbi->s_firstdatazone <= 4 ||
+	    sbi->s_firstdatazone >= sbi->s_nzones)
 		return false;
 
 	/*
-- 
2.51.2

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#syz test

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#syz test

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#syz test

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#syz test

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#syz test

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#syz test

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#syz dup: WARNING in ntfs_put_super

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---

diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
index 86a6b317b474..ee1760305380 100644
--- a/fs/hfs/dir.c
+++ b/fs/hfs/dir.c
@@ -196,8 +196,8 @@ static int hfs_create(struct mnt_idmap *idmap, struct inode *dir,
 	int res;
 
 	inode = hfs_new_inode(dir, &dentry->d_name, mode);
-	if (!inode)
-		return -ENOMEM;
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
 
 	res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
 	if (res) {
@@ -226,8 +226,8 @@ static struct dentry *hfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	int res;
 
 	inode = hfs_new_inode(dir, &dentry->d_name, S_IFDIR | mode);
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
 
 	res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
 	if (res) {
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 9cd449913dc8..beec6fe7e801 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -186,16 +186,23 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	s64 next_id;
 	s64 file_count;
 	s64 folder_count;
+	int err = -ENOMEM;
 
 	if (!inode)
-		return NULL;
+		goto out_err;
+
+	err = -ENOSPC;
 
 	mutex_init(&HFS_I(inode)->extents_lock);
 	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 	spin_lock_init(&HFS_I(inode)->open_dir_lock);
 	hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 	next_id = atomic64_inc_return(&HFS_SB(sb)->next_id);
-	BUG_ON(next_id > U32_MAX);
+	if (next_id > U32_MAX) {
+		pr_err("hfs: next file ID exceeds 32-bit limit — possible "
+		       "superblock corruption");
+		goto out_discard;
+	}
 	inode->i_ino = (u32)next_id;
 	inode->i_mode = mode;
 	inode->i_uid = current_fsuid();
@@ -209,7 +216,11 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	if (S_ISDIR(mode)) {
 		inode->i_size = 2;
 		folder_count = atomic64_inc_return(&HFS_SB(sb)->folder_count);
-		BUG_ON(folder_count > U32_MAX);
+		if (folder_count > U32_MAX) {
+			pr_err("hfs: folder count exceeds 32-bit limit — possible "
+			       "superblock corruption");
+			goto out_discard;
+		}
 		if (dir->i_ino == HFS_ROOT_CNID)
 			HFS_SB(sb)->root_dirs++;
 		inode->i_op = &hfs_dir_inode_operations;
@@ -219,7 +230,11 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	} else if (S_ISREG(mode)) {
 		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 		file_count = atomic64_inc_return(&HFS_SB(sb)->file_count);
-		BUG_ON(file_count > U32_MAX);
+		if (file_count > U32_MAX) {
+			pr_err("hfs: file count exceeds 32-bit limit — possible "
+			       "superblock corruption");
+			goto out_discard;
+		}
 		if (dir->i_ino == HFS_ROOT_CNID)
 			HFS_SB(sb)->root_files++;
 		inode->i_op = &hfs_file_inode_operations;
@@ -243,6 +258,11 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	hfs_mark_mdb_dirty(sb);
 
 	return inode;
+
+	out_discard:
+		iput(inode);	
+	out_err:
+		return ERR_PTR(err); 
 }
 
 void hfs_delete_inode(struct inode *inode)
@@ -251,7 +271,6 @@ void hfs_delete_inode(struct inode *inode)
 
 	hfs_dbg("ino %lu\n", inode->i_ino);
 	if (S_ISDIR(inode->i_mode)) {
-		BUG_ON(atomic64_read(&HFS_SB(sb)->folder_count) > U32_MAX);
 		atomic64_dec(&HFS_SB(sb)->folder_count);
 		if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 			HFS_SB(sb)->root_dirs--;
@@ -260,7 +279,6 @@ void hfs_delete_inode(struct inode *inode)
 		return;
 	}
 
-	BUG_ON(atomic64_read(&HFS_SB(sb)->file_count) > U32_MAX);
 	atomic64_dec(&HFS_SB(sb)->file_count);
 	if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 		HFS_SB(sb)->root_files--;
diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c
index 53f3fae60217..1c3fb631cc8e 100644
--- a/fs/hfs/mdb.c
+++ b/fs/hfs/mdb.c
@@ -273,15 +273,12 @@ void hfs_mdb_commit(struct super_block *sb)
 		/* These parameters may have been modified, so write them back */
 		mdb->drLsMod = hfs_mtime();
 		mdb->drFreeBks = cpu_to_be16(HFS_SB(sb)->free_ablocks);
-		BUG_ON(atomic64_read(&HFS_SB(sb)->next_id) > U32_MAX);
 		mdb->drNxtCNID =
 			cpu_to_be32((u32)atomic64_read(&HFS_SB(sb)->next_id));
 		mdb->drNmFls = cpu_to_be16(HFS_SB(sb)->root_files);
 		mdb->drNmRtDirs = cpu_to_be16(HFS_SB(sb)->root_dirs);
-		BUG_ON(atomic64_read(&HFS_SB(sb)->file_count) > U32_MAX);
 		mdb->drFilCnt =
 			cpu_to_be32((u32)atomic64_read(&HFS_SB(sb)->file_count));
-		BUG_ON(atomic64_read(&HFS_SB(sb)->folder_count) > U32_MAX);
 		mdb->drDirCnt =
 			cpu_to_be32((u32)atomic64_read(&HFS_SB(sb)->folder_count));
 
-- 
2.51.1.dirty

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---

diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
index 86a6b317b474..ee1760305380 100644
--- a/fs/hfs/dir.c
+++ b/fs/hfs/dir.c
@@ -196,8 +196,8 @@ static int hfs_create(struct mnt_idmap *idmap, struct inode *dir,
 	int res;
 
 	inode = hfs_new_inode(dir, &dentry->d_name, mode);
-	if (!inode)
-		return -ENOMEM;
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
 
 	res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
 	if (res) {
@@ -226,8 +226,8 @@ static struct dentry *hfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	int res;
 
 	inode = hfs_new_inode(dir, &dentry->d_name, S_IFDIR | mode);
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
 
 	res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
 	if (res) {
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index fff149af89da..6808b1316b60 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -273,4 +273,6 @@ static inline void hfs_bitmap_dirty(struct super_block *sb)
 	__bh;						\
 })
 
+#define EFSCORRUPTED   EUCLEAN         /* Filesystem is corrupted */
+
 #endif
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 9cd449913dc8..cb74904994cc 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -186,16 +186,22 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	s64 next_id;
 	s64 file_count;
 	s64 folder_count;
+	int err = -ENOMEM;
 
 	if (!inode)
-		return NULL;
+		goto out_err;
+
+	err = -EFSCORRUPTED;
 
 	mutex_init(&HFS_I(inode)->extents_lock);
 	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 	spin_lock_init(&HFS_I(inode)->open_dir_lock);
 	hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 	next_id = atomic64_inc_return(&HFS_SB(sb)->next_id);
-	BUG_ON(next_id > U32_MAX);
+	if (next_id > U32_MAX) {
+		printk(KERN_CRIT "hfs error: next file id on super block is corrupt");
+		goto out_discard;
+	}
 	inode->i_ino = (u32)next_id;
 	inode->i_mode = mode;
 	inode->i_uid = current_fsuid();
@@ -209,7 +215,10 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	if (S_ISDIR(mode)) {
 		inode->i_size = 2;
 		folder_count = atomic64_inc_return(&HFS_SB(sb)->folder_count);
-		BUG_ON(folder_count > U32_MAX);
+		if (folder_count > U32_MAX) {
+			printk(KERN_CRIT "hfs error: folder count on super block is corrupt");
+			goto out_discard;
+		}
 		if (dir->i_ino == HFS_ROOT_CNID)
 			HFS_SB(sb)->root_dirs++;
 		inode->i_op = &hfs_dir_inode_operations;
@@ -219,7 +228,10 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	} else if (S_ISREG(mode)) {
 		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 		file_count = atomic64_inc_return(&HFS_SB(sb)->file_count);
-		BUG_ON(file_count > U32_MAX);
+		if (file_count > U32_MAX) {
+			printk(KERN_CRIT "hfs error: file count on super block is corrupt");
+			goto out_discard;
+		}
 		if (dir->i_ino == HFS_ROOT_CNID)
 			HFS_SB(sb)->root_files++;
 		inode->i_op = &hfs_file_inode_operations;
@@ -243,6 +255,11 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
 	hfs_mark_mdb_dirty(sb);
 
 	return inode;
+
+	out_discard:
+		iput(inode);	
+	out_err:
+		return ERR_PTR(err); 
 }
 
 void hfs_delete_inode(struct inode *inode)

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---

diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
index 86a6b317b474..ee1760305380 100644
--- a/fs/hfs/dir.c
+++ b/fs/hfs/dir.c
@@ -196,8 +196,8 @@ static int hfs_create(struct mnt_idmap *idmap, struct inode *dir,
        int res;
 
        inode = hfs_new_inode(dir, &dentry->d_name, mode);
-       if (!inode)
-               return -ENOMEM;
+       if (IS_ERR(inode))
+               return PTR_ERR(inode);
 
        res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
        if (res) {
@@ -226,8 +226,8 @@ static struct dentry *hfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
        int res;
 
        inode = hfs_new_inode(dir, &dentry->d_name, S_IFDIR | mode);
-       if (!inode)
-               return ERR_PTR(-ENOMEM);
+       if (IS_ERR(inode))
+               return ERR_CAST(inode);
 
        res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
        if (res) {
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index fff149af89da..6808b1316b60 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -273,4 +273,6 @@ static inline void hfs_bitmap_dirty(struct super_block *sb)
        __bh;                                           \
 })
 
+#define EFSCORRUPTED   EUCLEAN         /* Filesystem is corrupted */
+
 #endif
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 9cd449913dc8..ef46a2d29d6a 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -188,7 +188,7 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
        s64 folder_count;
 
        if (!inode)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        mutex_init(&HFS_I(inode)->extents_lock);
        INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
@@ -209,7 +209,10 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
        if (S_ISDIR(mode)) {
                inode->i_size = 2;
                folder_count = atomic64_inc_return(&HFS_SB(sb)->folder_count);
-               BUG_ON(folder_count > U32_MAX);
+               if (folder_count > U32_MAX) {
+                       printk(KERN_CRIT "hfs error: folder count on super block is corrupt");
+                       return ERR_PTR(-EFSCORRUPTED);
+               }
                if (dir->i_ino == HFS_ROOT_CNID)
                        HFS_SB(sb)->root_dirs++;
                inode->i_op = &hfs_dir_inode_operations;
@@ -219,7 +222,10 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t
        } else if (S_ISREG(mode)) {
                HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
                file_count = atomic64_inc_return(&HFS_SB(sb)->file_count);
-               BUG_ON(file_count > U32_MAX);
+               if (file_count > U32_MAX) {
+                       printk(KERN_CRIT "hfs error: file count on super block is corrupt");
+                       return ERR_PTR(-EFSCORRUPTED);
+               }
                if (dir->i_ino == HFS_ROOT_CNID)
                        HFS_SB(sb)->root_files++;
                inode->i_op = &hfs_file_inode_operations;

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index d54273c3c9ff..ce62cb61186d 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -168,4 +168,6 @@ static inline int minix_test_bit(int nr, const void *vaddr)
 
 #endif
 
+#define EFSCORRUPTED   EUCLEAN         /* Filesystem is corrupted */
+
 #endif /* FS_MINIX_H */
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index a8d5a7e22b7b..f18f7474aca4 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -145,6 +145,12 @@ static int minix_unlink(struct inode * dir, struct dentry *dentry)
        struct minix_dir_entry * de;
        int err;
 
+       if (inode->i_nlink < 1) {
+               printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
+                      "has corrupted nlink", inode->i_ino);
+               return -EFSCORRUPTED;
+       }
+
        de = minix_find_entry(dentry, &folio);
        if (!de)
                return -ENOENT;
@@ -218,6 +224,13 @@ static int minix_rename(struct mnt_idmap *idmap,
                if (dir_de && !minix_empty_dir(new_inode))
                        goto out_dir;
 
+               err = -EFSCORRUPTED;
+               if (new_inode->i_nlink == 0 || (dir_de && new_inode->i_nlink != 2)) {
+                       printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
+                              "has corrupted nlink", new_inode->i_ino);
+                       goto out_dir;
+               }
+
                err = -ENOENT;
                new_de = minix_find_entry(new_dentry, &new_folio);
                if (!new_de)

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index aae1f32f4dab..f193912d8632 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -704,8 +704,8 @@ static void ntfs_put_super(struct super_block *sb)
        ntfs_set_state(sbi, NTFS_DIRTY_CLEAR);
 
        if (sbi->options) {
+               kfree(sbi->options->nls_name);
                unload_nls(sbi->options->nls);
-               kfree(sbi->options->nls);
                kfree(sbi->options);
                sbi->options = NULL;
        }
@@ -1670,8 +1670,8 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
        iput(inode);
 out:
        if (sbi && sbi->options) {
+               kfree(sbi->options->nls_name);
                unload_nls(sbi->options->nls);
-               kfree(sbi->options->nls);
                kfree(sbi->options);
                sbi->options = NULL;
        }

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---

diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index d54273c3c9ff..ce62cb61186d 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -168,4 +168,6 @@ static inline int minix_test_bit(int nr, const void *vaddr)
 
 #endif
 
+#define EFSCORRUPTED   EUCLEAN         /* Filesystem is corrupted */
+
 #endif /* FS_MINIX_H */
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index 8938536d8d3c..493a75eff2c9 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -208,6 +218,13 @@ static int minix_rename(struct mnt_idmap *idmap,
                if (dir_de && !minix_empty_dir(new_inode))
                        goto out_dir;
 
+               err = -EFSCORRUPTED;
+               if (new_inode->i_nlink == 0 || (dir_de && new_inode->i_nlink != 2)) {
+                       printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
+                              "has corrupted nlink", new_inode->i_ino);
+                       goto out_dir;
+               }
+
                err = -ENOENT;
                new_de = minix_find_entry(new_dentry, &new_folio);
                if (!new_de)

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index d54273c3c9ff..ce62cb61186d 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -168,4 +168,6 @@ static inline int minix_test_bit(int nr, const void *vaddr)
 
 #endif
 
+#define EFSCORRUPTED   EUCLEAN         /* Filesystem is corrupted */
+
 #endif /* FS_MINIX_H */

diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index a8d5a7e22b7b..8648d860ef0c 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -218,6 +218,13 @@ static int minix_rename(struct mnt_idmap *idmap,
                if (dir_de && !minix_empty_dir(new_inode))
                        goto out_dir;
 
+               err = -EFSCORRUPTED;
+               if (dir_de && new_inode->i_nlink != 2) {
+                       printk(KERN_CRIT "minix-fs error: directory inode has "
+                              "corrupted nlink");
+                       goto out_dir;
+               }
+
                err = -ENOENT;
                new_de = minix_find_entry(new_dentry, &new_folio);
                if (!new_de)

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---

diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index a8d5a7e22b7b..8648d860ef0c 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -218,6 +218,13 @@ static int minix_rename(struct mnt_idmap *idmap,
                if (dir_de && !minix_empty_dir(new_inode))
                        goto out_dir;
 
+               err = -EFSCORRUPTED;
+               if (dir_de && new_inode->i_nlink != 2) {
+                       printk(KERN_CRIT "minix-fs error: directory inode has "
+                              "corrupted nlink");
+                       goto out_dir;
+               }
+
                err = -ENOENT;
                new_de = minix_find_entry(new_dentry, &new_folio);
                if (!new_de)

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
 fs/minix/minix.h |  2 ++
 fs/minix/namei.c | 26 ++++++++++++++++++--------
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index d54273c3c9ff..ce62cb61186d 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -168,4 +168,6 @@ static inline int minix_test_bit(int nr, const void *vaddr)
 
 #endif
 
+#define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */
+
 #endif /* FS_MINIX_H */
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index 8938536d8d3c..a8d5a7e22b7b 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -161,15 +161,25 @@ static int minix_unlink(struct inode * dir, struct dentry *dentry)
 static int minix_rmdir(struct inode * dir, struct dentry *dentry)
 {
 	struct inode * inode = d_inode(dentry);
-	int err = -ENOTEMPTY;
-
-	if (minix_empty_dir(inode)) {
-		err = minix_unlink(dir, dentry);
-		if (!err) {
-			inode_dec_link_count(dir);
-			inode_dec_link_count(inode);
-		}
+	int err = -EFSCORRUPTED;
+
+	if (dir->i_nlink <= 2) {
+		printk(KERN_CRIT "minix-fs error: directory inode has "
+		       "corrupted nlink");
+		goto out;
 	}
+
+	err = -ENOTEMPTY;
+	if (!minix_empty_dir(inode))
+		goto out;
+
+	err = minix_unlink(dir, dentry);
+	if (!err) {
+		inode_dec_link_count(dir);
+		inode_dec_link_count(inode);
+ 	}
+
+out:
 	return err;
 }
 
-- 
2.51.1.dirty

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
 fs/jfs/jfs_dtree.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 0ab83bb7bbdf..e919de01c42a 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -170,8 +170,8 @@ static void dtGetKey(dtpage_t * p, int i, struct component_name * key,
 static int ciGetLeafPrefixKey(dtpage_t * lp, int li, dtpage_t * rp,
 			      int ri, struct component_name * key, int flag);
 
-static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
-			  ddata_t * data, struct dt_lock **);
+static int dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+			 ddata_t * data, struct dt_lock **);
 
 static void dtMoveEntry(dtpage_t * sp, int si, dtpage_t * dp,
 			struct dt_lock ** sdtlock, struct dt_lock ** ddtlock,
@@ -891,7 +891,8 @@ int dtInsert(tid_t tid, struct inode *ip,
 	lv->length = 1;
 	dtlck->index++;
 
-	dtInsertEntry(p, index, name, &data, &dtlck);
+	if (!(rc = dtInsertEntry(p, index, name, &data, &dtlck)))
+		return rc;
 
 	/* linelock stbl of non-root leaf page */
 	if (!(p->header.flag & BT_ROOT)) {
@@ -3625,9 +3626,10 @@ static void dtGetKey(dtpage_t * p, int i,	/* entry index */
  * function: allocate free slot(s) and
  *	     write a leaf/internal entry
  *
- * return: entry slot index
+ * * return: 0 - success;
+ *	   errno - failure;
  */
-static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+static int dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 			  ddata_t * data, struct dt_lock ** dtlock)
 {
 	struct dtslot *h, *t;
@@ -3649,6 +3651,10 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 
 	/* allocate a free slot */
 	hsi = fsi = p->header.freelist;
+	if (fsi >= ((p->header.flag & BT_ROOT) ? DTROOTMAXSLOT : p->header.maxslot)) {
+		jfs_err("Encountered corrupted dtpage before insert");
+		return -EIO;
+	}
 	h = &p->slot[fsi];
 	p->header.freelist = h->next;
 	--p->header.freecnt;
@@ -3697,6 +3703,10 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 	while (klen) {
 		/* get free slot */
 		fsi = p->header.freelist;
+		if (fsi >= ((p->header.flag & BT_ROOT) ? DTROOTMAXSLOT : p->header.maxslot)) {
+			jfs_err("Encountered corrupted dtpage before insert");
+			return -EIO;
+		}
 		t = &p->slot[fsi];
 		p->header.freelist = t->next;
 		--p->header.freecnt;
@@ -3774,6 +3784,8 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 
 	/* advance next available entry index of stbl */
 	++p->header.nextindex;
+
+	return 0;
 }
 
 
-- 
2.51.1.dirty

Re: Forwarded:

[Al Viro]

On Tue, Oct 28, 2025 at 10:25:20AM -0700, syzbot wrote:
> For archival purposes, forwarding an incoming command email to
> linux-kernel@vger.kernel.org.

For fuck sake, either generate a more useful subject, or take
that to a separate list just for syzbot use.

Do you really intend to end up in a bunch of .procmailrc?

Forwarded:

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***

Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
 fs/jfs/jfs_dtree.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 0ab83bb7bbdf..e919de01c42a 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -170,8 +170,8 @@ static void dtGetKey(dtpage_t * p, int i, struct component_name * key,
 static int ciGetLeafPrefixKey(dtpage_t * lp, int li, dtpage_t * rp,
 			      int ri, struct component_name * key, int flag);
 
-static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
-			  ddata_t * data, struct dt_lock **);
+static int dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+			 ddata_t * data, struct dt_lock **);
 
 static void dtMoveEntry(dtpage_t * sp, int si, dtpage_t * dp,
 			struct dt_lock ** sdtlock, struct dt_lock ** ddtlock,
@@ -891,7 +891,8 @@ int dtInsert(tid_t tid, struct inode *ip,
 	lv->length = 1;
 	dtlck->index++;
 
-	dtInsertEntry(p, index, name, &data, &dtlck);
+	if (!(rc = dtInsertEntry(p, index, name, &data, &dtlck)))
+		return rc;
 
 	/* linelock stbl of non-root leaf page */
 	if (!(p->header.flag & BT_ROOT)) {
@@ -3625,9 +3626,10 @@ static void dtGetKey(dtpage_t * p, int i,	/* entry index */
  * function: allocate free slot(s) and
  *	     write a leaf/internal entry
  *
- * return: entry slot index
+ * * return: 0 - success;
+ *	   errno - failure;
  */
-static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+static int dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 			  ddata_t * data, struct dt_lock ** dtlock)
 {
 	struct dtslot *h, *t;
@@ -3649,6 +3651,10 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 
 	/* allocate a free slot */
 	hsi = fsi = p->header.freelist;
+	if (fsi >= ((p->header.flag & BT_ROOT) ? DTROOTMAXSLOT : p->header.maxslot)) {
+		jfs_err("Encountered corrupted dtpage before insert");
+		return -EIO;
+	}
 	h = &p->slot[fsi];
 	p->header.freelist = h->next;
 	--p->header.freecnt;
@@ -3697,6 +3703,10 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 	while (klen) {
 		/* get free slot */
 		fsi = p->header.freelist;
+		if (fsi >= ((p->header.flag & BT_ROOT) ? DTROOTMAXSLOT : p->header.maxslot)) {
+			jfs_err("Encountered corrupted dtpage before insert");
+			return -EIO;
+		}
 		t = &p->slot[fsi];
 		p->header.freelist = t->next;
 		--p->header.freecnt;
@@ -3774,6 +3784,8 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 
 	/* advance next available entry index of stbl */
 	++p->header.nextindex;
+
+	return 0;
 }
 
 
-- 
2.51.1.dirty

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 0ab83bb7bbdf..07dd01c79ca2 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -170,8 +170,8 @@ static void dtGetKey(dtpage_t * p, int i, struct component_name * key,
 static int ciGetLeafPrefixKey(dtpage_t * lp, int li, dtpage_t * rp,
 			      int ri, struct component_name * key, int flag);
 
-static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
-			  ddata_t * data, struct dt_lock **);
+static int dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+			 ddata_t * data, struct dt_lock **);
 
 static void dtMoveEntry(dtpage_t * sp, int si, dtpage_t * dp,
 			struct dt_lock ** sdtlock, struct dt_lock ** ddtlock,
@@ -891,7 +891,8 @@ int dtInsert(tid_t tid, struct inode *ip,
 	lv->length = 1;
 	dtlck->index++;
 
-	dtInsertEntry(p, index, name, &data, &dtlck);
+	if (!(rc = dtInsertEntry(p, index, name, &data, &dtlck)))
+		return rc;
 
 	/* linelock stbl of non-root leaf page */
 	if (!(p->header.flag & BT_ROOT)) {
@@ -3627,7 +3628,7 @@ static void dtGetKey(dtpage_t * p, int i,	/* entry index */
  *
  * return: entry slot index
  */
-static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+static int dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 			  ddata_t * data, struct dt_lock ** dtlock)
 {
 	struct dtslot *h, *t;
@@ -3649,6 +3650,10 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 
 	/* allocate a free slot */
 	hsi = fsi = p->header.freelist;
+	if (fsi >= p->header.maxslot) {
+		jfs_err("Encountered corrupted dtpage before insert");
+		return -EIO;
+	}
 	h = &p->slot[fsi];
 	p->header.freelist = h->next;
 	--p->header.freecnt;
@@ -3697,6 +3702,10 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 	while (klen) {
 		/* get free slot */
 		fsi = p->header.freelist;
+		if (fsi >= p->header.maxslot) {
+			jfs_err("Encountered corrupted dtpage before insert");
+			return -EIO;
+		}
 		t = &p->slot[fsi];
 		p->header.freelist = t->next;
 		--p->header.freecnt;
@@ -3774,6 +3783,8 @@ static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
 
 	/* advance next available entry index of stbl */
 	++p->header.nextindex;
+
+	return 0;
 }

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Subject: 
Author: kubik.bartlomiej@gmail.com

#syz test

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Subject: 
Author: zlatistiv@gmail.com

#syz test

Forwarded:

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***

Subject: 
Author: clf700383@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master

From 6dc2deb09faf7d53707cc9e75e175b09644fd181 Mon Sep 17 00:00:00 2001
From: clingfei <clf700383@gmail.com>
Date: Mon, 20 Oct 2025 13:48:54 +0800
Subject: [PATCH] fix integer overflow in set_ipsecrequest

syzbot reported a kernel BUG in set_ipsecrequest() due to an skb_over_panic.

The mp->new_family and mp->old_family is u16, while set_ipsecrequest receives
family as uint8_t,  causing a integer overflow and the later size_req calculation
error, which exceeds the size used in alloc_skb, and ultimately triggered the
kernel bug in skb_put.

Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
Signed-off-by: Cheng Lingfei <clf700383@gmail.com>
---
 net/key/af_key.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2ebde0352245..08f4cde01994 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3518,7 +3518,7 @@ static int set_sadb_kmaddress(struct sk_buff *skb, const struct xfrm_kmaddress *
 
 static int set_ipsecrequest(struct sk_buff *skb,
 			    uint8_t proto, uint8_t mode, int level,
-			    uint32_t reqid, uint8_t family,
+			    uint32_t reqid, uint16_t family,
 			    const xfrm_address_t *src, const xfrm_address_t *dst)
 {
 	struct sadb_x_ipsecrequest *rq;
-- 
2.34.1

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
 fs/minix/inode.c | 14 ++++++++++++++
 fs/minix/namei.c | 22 ++++++++++++++--------
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index f007e389d5d2..e27907fc9bf2 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -517,6 +517,13 @@ static struct inode *V1_minix_iget(struct inode *inode)
 		iget_failed(inode);
 		return ERR_PTR(-ESTALE);
 	}
+	if (S_ISDIR(raw_inode->i_mode) && raw_inode->i_nlinks == 1) {
+		printk("MINIX-fs: directory inode (%lu) has single i_nlink\n",
+		       inode->i_ino);
+		brelse(bh);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
+	}
 	inode->i_mode = raw_inode->i_mode;
 	i_uid_write(inode, raw_inode->i_uid);
 	i_gid_write(inode, raw_inode->i_gid);
@@ -555,6 +562,13 @@ static struct inode *V2_minix_iget(struct inode *inode)
 		iget_failed(inode);
 		return ERR_PTR(-ESTALE);
 	}
+	if (S_ISDIR(raw_inode->i_mode) && raw_inode->i_nlinks == 1) {
+		printk("MINIX-fs: directory inode (%lu) has single i_nlink\n",
+		       inode->i_ino);
+		brelse(bh);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
+	}
 	inode->i_mode = raw_inode->i_mode;
 	i_uid_write(inode, raw_inode->i_uid);
 	i_gid_write(inode, raw_inode->i_gid);
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index 8938536d8d3c..8297ee6651a1 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -161,15 +161,21 @@ static int minix_unlink(struct inode * dir, struct dentry *dentry)
 static int minix_rmdir(struct inode * dir, struct dentry *dentry)
 {
 	struct inode * inode = d_inode(dentry);
-	int err = -ENOTEMPTY;
-
-	if (minix_empty_dir(inode)) {
-		err = minix_unlink(dir, dentry);
-		if (!err) {
-			inode_dec_link_count(dir);
-			inode_dec_link_count(inode);
-		}
+	int err = -EIO;
+
+	if (dir->i_nlink <= 2)
+		goto out;
+
+	err = -ENOTEMPTY;
+	if (!minix_empty_dir(inode))
+		goto out;
+
+	err = minix_unlink(dir, dentry);
+	if (!err) {
+		inode_dec_link_count(dir);
+		inode_dec_link_count(inode);
 	}
+out:
 	return err;
 }
 
-- 
2.51.0

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
 fs/minix/inode.c | 14 ++++++++++++++
 fs/minix/namei.c | 22 ++++++++++++++--------
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index f007e389d5d2..e27907fc9bf2 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -517,6 +517,13 @@ static struct inode *V1_minix_iget(struct inode *inode)
 		iget_failed(inode);
 		return ERR_PTR(-ESTALE);
 	}
+	if (S_ISDIR(raw_inode->i_mode) && raw_inode->i_nlinks == 1) {
+		printk("MINIX-fs: directory inode (%lu) has single i_nlink\n",
+		       inode->i_ino);
+		brelse(bh);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
+	}
 	inode->i_mode = raw_inode->i_mode;
 	i_uid_write(inode, raw_inode->i_uid);
 	i_gid_write(inode, raw_inode->i_gid);
@@ -555,6 +562,13 @@ static struct inode *V2_minix_iget(struct inode *inode)
 		iget_failed(inode);
 		return ERR_PTR(-ESTALE);
 	}
+	if (S_ISDIR(raw_inode->i_mode) && raw_inode->i_nlinks == 1) {
+		printk("MINIX-fs: directory inode (%lu) has single i_nlink\n",
+		       inode->i_ino);
+		brelse(bh);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
+	}
 	inode->i_mode = raw_inode->i_mode;
 	i_uid_write(inode, raw_inode->i_uid);
 	i_gid_write(inode, raw_inode->i_gid);
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index 8938536d8d3c..8297ee6651a1 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -161,15 +161,21 @@ static int minix_unlink(struct inode * dir, struct dentry *dentry)
 static int minix_rmdir(struct inode * dir, struct dentry *dentry)
 {
 	struct inode * inode = d_inode(dentry);
-	int err = -ENOTEMPTY;
-
-	if (minix_empty_dir(inode)) {
-		err = minix_unlink(dir, dentry);
-		if (!err) {
-			inode_dec_link_count(dir);
-			inode_dec_link_count(inode);
-		}
+	int err = -EIO;
+
+	if (dir->i_nlink <= 2)
+		goto out;
+
+	err = -ENOTEMPTY;
+	if (!minix_empty_dir(inode))
+		goto out;
+
+	err = minix_unlink(dir, dentry);
+	if (!err) {
+		inode_dec_link_count(dir);
+		inode_dec_link_count(inode);
 	}
+out:
 	return err;
 }
 
-- 
2.51.0

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
fs/minix/namei.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index 8938536d8d3c..86779a6ec1a7 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -224,7 +224,7 @@ static int minix_rename(struct mnt_idmap *idmap,
err = minix_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
- if (dir_de)
+ if (dir_de && old_dir != new_dir)
inode_inc_link_count(new_dir);
}
@@ -236,7 +236,7 @@ static int minix_rename(struct mnt_idmap *idmap,
if (dir_de) {
err = minix_set_link(dir_de, dir_folio, new_dir);
- if (!err)
+ if (!err && (new_inode || old_dir != new_dir))
inode_dec_link_count(old_dir);
}
out_dir:
-- 
2.51.0

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
 fs/jfs/namei.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 65a218eba8fa..7879c049632b 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -1228,7 +1228,7 @@ static int jfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 				jfs_err("jfs_rename: dtInsert returned -EIO");
 			goto out_tx;
 		}
-		if (S_ISDIR(old_ip->i_mode))
+		if (S_ISDIR(old_ip->i_mode) && old_dir != new_dir)
 			inc_nlink(new_dir);
 	}
 	/*
@@ -1244,7 +1244,9 @@ static int jfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		goto out_tx;
 	}
 	if (S_ISDIR(old_ip->i_mode)) {
-		drop_nlink(old_dir);
+		if (new_ip || old_dir != new_dir)
+			drop_nlink(old_dir);
+
 		if (old_dir != new_dir) {
 			/*
 			 * Change inode number of parent for moved directory
-- 
2.51.0

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test

---
 fs/jfs/namei.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 65a218eba8fa..37cd16a423c5 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -1228,7 +1228,7 @@ static int jfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 				jfs_err("jfs_rename: dtInsert returned -EIO");
 			goto out_tx;
 		}
-		if (S_ISDIR(old_ip->i_mode))
+		if (S_ISDIR(old_ip->i_mode) && old_dir != new_dir)
 			inc_nlink(new_dir);
 	}
 	/*
@@ -1244,8 +1244,9 @@ static int jfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		goto out_tx;
 	}
 	if (S_ISDIR(old_ip->i_mode)) {
-		drop_nlink(old_dir);
 		if (old_dir != new_dir) {
+			drop_nlink(old_dir);
+
 			/*
 			 * Change inode number of parent for moved directory
 			 */
-- 
2.51.0

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Subject: 
Author: jkoolstra@xs4all.nl

#syz test


 fs/ntfs3/index.c | 10 +++++-----
 fs/ntfs3/ntfs.h  |  5 ++++-
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index 6d1bf890929d..2e512abc7000 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -1808,7 +1808,7 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni,
 	CLST new_vbn;
 	__le64 t_vbn, *sub_vbn;
 	u16 sp_size;
-	void *hdr1_saved = NULL;
+	void *blk1_saved = NULL;
 
 	/* Try the most easy case. */
 	e = fnd->level - 1 == level ? fnd->de[level] : NULL;
@@ -1842,8 +1842,8 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni,
 	memcpy(up_e, sp, sp_size);
 
 	used1 = le32_to_cpu(hdr1->used);
-	hdr1_saved = kmemdup(hdr1, used1, GFP_NOFS);
-	if (!hdr1_saved) {
+	blk1_saved = kmemdup(&n1->index->blk, used1, GFP_NOFS);
+	if (!blk1_saved) {
 		err = -ENOMEM;
 		goto out;
 	}
@@ -1924,13 +1924,13 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni,
 		 * Undo critical operations.
 		 */
 		indx_mark_free(indx, ni, new_vbn >> indx->idx2vbn_bits);
-		memcpy(hdr1, hdr1_saved, used1);
+		memcpy(&n1->index->blk, blk1_saved, used1);
 		indx_write(indx, ni, n1, 0);
 	}
 
 out:
 	kfree(up_e);
-	kfree(hdr1_saved);
+	kfree(blk1_saved);
 
 	return err;
 }
diff --git a/fs/ntfs3/ntfs.h b/fs/ntfs3/ntfs.h
index 552b97905813..d5e2b22eacd7 100644
--- a/fs/ntfs3/ntfs.h
+++ b/fs/ntfs3/ntfs.h
@@ -754,7 +754,10 @@ static inline bool hdr_has_subnode(const struct INDEX_HDR *hdr)
 struct INDEX_BUFFER {
 	struct NTFS_RECORD_HEADER rhdr; // 'INDX'
 	__le64 vbn; // 0x10: vcn if index >= cluster or vsn id index < cluster
-	struct INDEX_HDR ihdr; // 0x18:
+	struct_group(blk,
+		struct INDEX_HDR ihdr; // 0x18:
+	        u8 data[]; // NTFS_DE entries
+	);
 };
 
 static_assert(sizeof(struct INDEX_BUFFER) == 0x28);
-- 
2.51.0

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Subject: 
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#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

Resending this patch in the existing thread with a '#syz test:' directive
so syzbot can test it.

From 1bb35c6722b8fb03e9262f6e6530d240629a44df Mon Sep 17 00:00:00 2001
From: neqbal <nooraineqbal@gmail.com>
Date: Sun, 28 Sep 2025 03:52:44 +0530
Subject: [PATCH] x86/mm: Fix off-by-one error in set_memory

Correct end page calculation by subtracting 1 to prevent
out-of-bounds access.

Reported-by: syzbot+e34177f6091df113ef20@syzkaller.appspotmail.com
Signed-off-by: neqbal <nooraineqbal@gmail.com>
---
 arch/x86/mm/pat/set_memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index d2d54b8c4dbb..daefc96403f1 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -446,7 +446,7 @@ static void cpa_flush(struct cpa_data *cpa, int cache)
 	}
 
 	start = fix_addr(__cpa_addr(cpa, 0));
-	end =   fix_addr(__cpa_addr(cpa, cpa->numpages));
+	end =   fix_addr(__cpa_addr(cpa, cpa->numpages - 1));
 	if (cpa->force_flush_all)
 		end = TLB_FLUSH_ALL;
 
-- 
2.51.0

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#syz test

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 26d6c1eea559..a879e8030568 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -760,7 +760,7 @@ static int compute_bitstructs(struct gfs2_rgrpd *rgd)
        u32 bytes_left, bytes;
        int x;

-       if (!length)
+       if (!length || length > KMALLOC_MAX_SIZE / sizeof(struct
gfs2_bitmap))
                return -EINVAL;

        rgd->rd_bits = kcalloc(length, sizeof(struct gfs2_bitmap),
GFP_NOFS);

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#syz test

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#syz invalid

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no longer relevant

#syz invalid

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#syz test

--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -33,6 +33,12 @@ static int ovl_cleanup_locked(struct dentry *workdir,
struct dentry *dentry)
        struct inode *dir = d_inode(workdir);
        struct inode *inode = d_inode(dentry);

+ /* Avoid unlinking an already unlinked inode */
+ if (inode && inode->i_nlink == 0) {
+ d_drop(dentry);
+ return 0;
+ }
+
        if (ovl_is_whiteout(dentry))
                return ovl_remove_and_whiteout(workdir, dentry, true);

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#syz test

--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -872,6 +872,11 @@ static int ax88772_bind(struct usbnet *dev, struct
usb_interface *intf)
        if (ret < 0)
                return ret;

+ if (ret >= 32) {
+ netdev_warn(dev->net, "Invalid PHY address %d, clamping\n", ret);
+ return -EINVAL;
+ }
+
        priv->phy_addr = ret;
        priv->embd_phy = ((priv->phy_addr & 0x1f) == AX_EMBD_PHY_ADDR);


--

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