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syzkaller-bugs@googlegroups.com, varun.singh10011@gmail.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: KASAN: slab-use-after-free Read in check_tty_count ================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:82 [inline] BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: slab-use-after-free in tty_port_kopened include/linux/tty_port.h:234 [inline] BUG: KASAN: slab-use-after-free in check_tty_count+0x134/0x2b0 drivers/tty/tty_io.c:287 Read of size 8 at addr ffff88802fb2d230 by task syz.1.18/6460 CPU: 0 UID: 0 PID: 6460 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200 instrument_atomic_read include/linux/instrumented.h:82 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] tty_port_kopened include/linux/tty_port.h:234 [inline] check_tty_count+0x134/0x2b0 drivers/tty/tty_io.c:287 tty_release+0x95/0x1300 drivers/tty/tty_io.c:1703 __fput+0x3fb/0xb50 fs/file_table.c:512 fput_close_sync+0x118/0x250 fs/file_table.c:618 filp_close_sync+0x75/0xa0 fs/open.c:1573 __range_close+0x4a6/0x8b0 fs/file.c:919 __do_sys_close_range fs/file.c:1003 [inline] __se_sys_close_range fs/file.c:954 [inline] __x64_sys_close_range+0x1f8/0x430 fs/file.c:954 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2c3f39e0d9 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:00007ffe8f94f768 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: ffffffffffffffda RBX: 00007f2c3f627da0 RCX: 00007f2c3f39e0d9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f2c3f627da0 R08: 00007f2c3f626038 R09: 0000000000000000 R10: 000000000003fda0 R11: 0000000000000246 R12: 0000000000016d7e R13: 00007f2c3f625fac R14: 0000000000016aa0 R15: 00007ffe8f94f870 Allocated by task 6461: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5680 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] gs_port_alloc drivers/usb/gadget/function/u_serial.c:1218 [inline] gserial_alloc_line_no_console+0xac/0x710 drivers/usb/gadget/function/u_serial.c:1298 gserial_alloc_line+0x16/0xa0 drivers/usb/gadget/function/u_serial.c:1332 acm_alloc_instance+0xd9/0x160 drivers/usb/gadget/function/f_acm.c:891 try_get_usb_function_instance+0x136/0x1f0 drivers/usb/gadget/functions.c:28 usb_get_function_instance+0x16/0x70 drivers/usb/gadget/functions.c:44 function_make+0x18c/0x3f0 drivers/usb/gadget/configfs.c:626 configfs_mkdir+0x525/0xd40 fs/configfs/dir.c:1369 vfs_mkdir+0x36d/0x8a0 fs/namei.c:5428 filename_mkdirat+0x4c4/0x630 fs/namei.c:5461 __do_sys_mkdirat fs/namei.c:5482 [inline] __se_sys_mkdirat fs/namei.c:5479 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5479 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6461: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2780 [inline] slab_free mm/slub.c:6630 [inline] kfree+0x22b/0x6d0 mm/slub.c:6923 gserial_free_port+0x141/0x2f0 drivers/usb/gadget/function/u_serial.c:1262 gserial_free_line+0xf8/0x1e0 drivers/usb/gadget/function/u_serial.c:1279 acm_free_instance+0x3b/0x60 drivers/usb/gadget/function/f_acm.c:875 usb_put_function_instance+0x97/0xc0 drivers/usb/gadget/functions.c:77 config_item_cleanup+0x146/0x240 fs/configfs/item.c:128 config_item_release fs/configfs/item.c:137 [inline] kref_put include/linux/kref.h:65 [inline] config_item_put fs/configfs/item.c:149 [inline] config_item_put+0x93/0xb0 fs/configfs/item.c:146 configfs_rmdir+0x5e3/0x950 fs/configfs/dir.c:1580 vfs_rmdir fs/namei.c:5533 [inline] vfs_rmdir+0x328/0x8e0 fs/namei.c:5506 filename_rmdir+0x31a/0x610 fs/namei.c:5590 __do_sys_rmdir fs/namei.c:5613 [inline] __se_sys_rmdir fs/namei.c:5610 [inline] __x64_sys_rmdir+0x46/0x70 fs/namei.c:5610 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802fb2d000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 560 bytes inside of freed 2048-byte region [ffff88802fb2d000, ffff88802fb2d800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2fb28 head: order:3 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 ffff88801c442f00 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801c442f00 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5732, tgid 5732 (syz-executor), ts 48781510074 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1856 prep_new_page mm/page_alloc.c:1864 [inline] get_page_from_freelist+0x1113/0x35e0 mm/page_alloc.c:3935 __alloc_frozen_pages_noprof+0x2bd/0x3280 mm/page_alloc.c:5444 alloc_slab_page mm/slub.c:3384 [inline] allocate_slab mm/slub.c:3499 [inline] new_slab+0xb1/0x6d0 mm/slub.c:3550 refill_objects+0xe3/0x410 mm/slub.c:7539 refill_sheaf mm/slub.c:2917 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4811 alloc_from_pcs mm/slub.c:4887 [inline] slab_alloc_node mm/slub.c:5021 [inline] __do_kmalloc_node mm/slub.c:5530 [inline] __kmalloc_node_track_caller_noprof+0x6a3/0x870 mm/slub.c:5662 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:638 __alloc_skb+0x185/0x710 net/core/skbuff.c:716 alloc_skb include/linux/skbuff.h:1390 [inline] nlmsg_new include/net/netlink.h:1055 [inline] rtmsg_ifinfo_build_skb+0x81/0x260 net/core/rtnetlink.c:4617 rtmsg_ifinfo_event net/core/rtnetlink.c:4659 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4649 [inline] rtnetlink_event+0x137/0x1f0 net/core/rtnetlink.c:7229 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:86 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2313 call_netdevice_notifiers_extack net/core/dev.c:2351 [inline] call_netdevice_notifiers net/core/dev.c:2365 [inline] netif_set_mac_address+0x370/0x4a0 net/core/dev.c:10235 do_setlink.isra.0+0x75f/0x3f50 net/core/rtnetlink.c:3246 rtnl_changelink net/core/rtnetlink.c:3942 [inline] __rtnl_newlink net/core/rtnetlink.c:4113 [inline] rtnl_newlink+0x13c1/0x2620 net/core/rtnetlink.c:4252 page last free pid 5726 tgid 5722 ts 45751756529 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1403 [inline] __free_frozen_pages+0x7b4/0x1110 mm/page_alloc.c:2954 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4720 [inline] slab_alloc_node mm/slub.c:5033 [inline] kmem_cache_alloc_lru_noprof+0x265/0x6a0 mm/slub.c:5066 __d_alloc+0x34/0xad0 fs/dcache.c:1945 __d_alloc_parallel+0x105/0x15e0 fs/dcache.c:2879 lookup_open+0x6c4/0x19e0 fs/namei.c:4479 open_last_lookups fs/namei.c:4774 [inline] path_openat+0xe75/0x23f0 fs/namei.c:5013 do_file_open+0x20e/0x430 fs/namei.c:5045 do_sys_openat2+0x163/0x1d0 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802fb2d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802fb2d180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802fb2d200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802fb2d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802fb2d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Tested on: commit: cbbddb6b Merge tag 'power-utilities-2026.10.31' of git.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=176eed29580000 kernel config: https://syzkaller.appspot.com/x/.config?x=245a52f53bb4b06b dashboard link: https://syzkaller.appspot.com/bug?extid=39a2135de1558208d3b3 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Note: no patches were applied.