* [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvme_query_zone_info
@ 2026-10-02 1:22 syzbot
2026-10-02 1:37 ` syzbot
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: syzbot @ 2026-10-02 1:22 UTC (permalink / raw)
To: axboe, hch, kbusch, linux-kernel, linux-nvme, sagi, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: fd179f8a05be Merge tag 'ata-7.3-rc5' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13317d25580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7d012d9c67977ee4
dashboard link: https://syzkaller.appspot.com/bug?extid=76c0f0ce8f1e846b4f84
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/85c6caf0d8ad/disk-fd179f8a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9df42cc34c1c/vmlinux-fd179f8a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/da4a5ee29c56/bzImage-fd179f8a.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+76c0f0ce8f1e846b4f84@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in nvme_query_zone_info+0x4fd/0x6f0 drivers/nvme/host/zns.c:47
Read of size 4 at addr ffff88802ab9e5f4 by task kworker/u8:2/43
CPU: 0 UID: 0 PID: 43 Comm: kworker/u8:2 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: async async_run_entry_fn
Call Trace:
<TASK>
__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
nvme_query_zone_info+0x4fd/0x6f0 drivers/nvme/host/zns.c:47
nvme_update_ns_info_block+0x1b2e/0x2af0 drivers/nvme/host/core.c:2430
nvme_update_ns_info+0xc6/0xd90 drivers/nvme/host/core.c:2553
nvme_alloc_ns+0x1a9f/0x3e50 drivers/nvme/host/core.c:4293
nvme_scan_ns+0x79d/0x910 drivers/nvme/host/core.c:4483
async_run_entry_fn+0x9f/0x580 kernel/async.c:129
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 6345:
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:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
nvme_get_effects_log+0x13a/0x280 drivers/nvme/host/core.c:3422
nvme_alloc_ns_head drivers/nvme/host/core.c:4037 [inline]
nvme_init_ns_head drivers/nvme/host/core.c:4153 [inline]
nvme_alloc_ns+0x25f0/0x3e50 drivers/nvme/host/core.c:4267
nvme_scan_ns+0x79d/0x910 drivers/nvme/host/core.c:4483
async_run_entry_fn+0x9f/0x580 kernel/async.c:129
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Freed by task 14867:
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:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6508 [inline]
kfree+0x22b/0x6d0 mm/slub.c:6801
nvme_free_cels drivers/nvme/host/core.c:5165 [inline]
nvme_free_ctrl+0x1e4/0x6b0 drivers/nvme/host/core.c:5183
device_release+0xd2/0x270 drivers/base/core.c:2640
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1f7/0x640 lib/kobject.c:737
put_device+0x1f/0x30 drivers/base/core.c:3884
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
The buggy address belongs to the object at ffff88802ab9e000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1524 bytes inside of
freed 4096-byte region [ffff88802ab9e000, ffff88802ab9f000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ab98
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 ffff88801c035140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801c035140 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4966, tgid 4966 (udevd), ts 17565154748
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab mm/slub.c:3462 [inline]
new_slab+0xa9/0x6e0 mm/slub.c:3513
refill_objects+0xe3/0x410 mm/slub.c:7417
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__do_kmalloc_node mm/slub.c:5413 [inline]
__kmalloc_noprof+0x67c/0x840 mm/slub.c:5439
_kmalloc_noprof include/linux/slab.h:995 [inline]
tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x2af/0x3c0 security/tomoyo/file.c:776
tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334
security_file_open+0xb5/0x1e0 security/security.c:2739
do_dentry_open+0x588/0x14d0 fs/open.c:973
vfs_open+0x82/0x3f0 fs/open.c:1101
do_open fs/namei.c:4837 [inline]
path_openat+0x19fa/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
page last free pid 4966 tgid 4966 ts 17563576089 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962
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:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_node_noprof+0x282/0x6e0 mm/slub.c:5068
kmalloc_reserve+0x148/0x350 net/core/skbuff.c:615
__alloc_skb+0x185/0x710 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
netlink_alloc_large_skb+0x69/0x150 net/netlink/af_netlink.c:1204
netlink_sendmsg+0x680/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713
___sys_sendmsg+0x190/0x1e0 net/socket.c:2767
__sys_sendmsg+0x160/0x210 net/socket.c:2799
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:
ffff88802ab9e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802ab9e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802ab9e580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802ab9e600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802ab9e680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvme_query_zone_info
2026-10-02 1:22 [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvme_query_zone_info syzbot
@ 2026-10-02 1:37 ` syzbot
2026-10-02 12:58 ` Forwarded: [PATCH] nvme: hold a controller reference while scan_work is queued or running syzbot
2026-10-02 16:30 ` [PATCH] nvme: keep the effects log per namespace path, not in the shared head Nguyen Ngoc Thang
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2026-10-02 1:37 UTC (permalink / raw)
To: axboe, hch, kbusch, linux-kernel, linux-nvme, sagi, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: d24e8ac715de Merge tag 'net-7.3-rc6' of git://git.kernel.o..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16c2d3f5580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7d012d9c67977ee4
dashboard link: https://syzkaller.appspot.com/bug?extid=76c0f0ce8f1e846b4f84
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17a1cbf5580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+76c0f0ce8f1e846b4f84@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in nvme_query_zone_info+0x4fd/0x6f0 drivers/nvme/host/zns.c:47
Read of size 4 at addr ffff88803745a5f4 by task kworker/u8:13/5985
CPU: 0 UI
CPU: 0 UID: 0 PID: 5985 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Workqueue: async async_run_entry_fn
Call Trace:
<TASK>
__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
nvme_query_zone_info+0x4fd/0x6f0 drivers/nvme/host/zns.c:47
nvme_update_ns_info_block+0x1b2e/0x2af0 drivers/nvme/host/core.c:2430
nvme_update_ns_info+0xc6/0xd90 drivers/nvme/host/core.c:2553
nvme_alloc_ns+0x1a9f/0x3e50 drivers/nvme/host/core.c:4293
nvme_scan_ns+0x79d/0x910 drivers/nvme/host/core.c:4483
async_run_entry_fn+0x9f/0x580 kernel/async.c:129
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 13:
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:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
nvme_get_effects_log+0x13a/0x280 drivers/nvme/host/core.c:3422
nvme_alloc_ns_head drivers/nvme/host/core.c:4037 [inline]
nvme_init_ns_head drivers/nvme/host/core.c:4153 [inline]
nvme_alloc_ns+0x25f0/0x3e50 drivers/nvme/host/core.c:4267
nvme_scan_ns+0x79d/0x910 drivers/nvme/host/core.c:4483
async_run_entry_fn+0x9f/0x580 kernel/async.c:129
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Freed by task 5948:
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:2748 [inline]
slab_free mm/slub.c:6508 [inline]
kfree+0x22b/0x6d0 mm/slub.c:6801
nvme_free_cels drivers/nvme/host/core.c:5165 [inline]
nvme_free_ctrl+0x1e4/0x6b0 drivers/nvme/host/core.c:5183
device_release+0xd2/0x270 drivers/base/core.c:2640
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1f7/0x640 lib/kobject.c:737
put_device+0x1f/0x30 drivers/base/core.c:3884
nvme_sysfs_delete+0xc9/0xf0 drivers/nvme/host/sysfs.c:500
dev_attr_store+0x58/0x80 drivers/base/core.c:2509
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
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 ffff88803745a000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1524 bytes inside of
freed 4096-byte region [ffff88803745a000, ffff88803745b000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x37458
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 ffff88801c032140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801c032140 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4974, tgid 4974 (udevd), ts 23285385277
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab mm/slub.c:3462 [inline]
new_slab+0xa9/0x6e0 mm/slub.c:3513
refill_objects+0xe3/0x410 mm/slub.c:7417
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__do_kmalloc_node mm/slub.c:5413 [inline]
__kmalloc_noprof+0x67c/0x840 mm/slub.c:5439
_kmalloc_noprof include/linux/slab.h:995 [inline]
tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x2af/0x3c0 security/tomoyo/file.c:776
tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334
security_file_open+0xb5/0x1e0 security/security.c:2739
do_dentry_open+0x588/0x14d0 fs/open.c:973
vfs_open+0x82/0x3f0 fs/open.c:1101
do_open fs/namei.c:4837 [inline]
path_openat+0x19fa/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
page last free pid 4967 tgid 4967 ts 22520049234 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962
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:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010
alloc_filename fs/namei.c:147 [inline]
do_getname+0x35/0x390 fs/namei.c:187
class_filename_flags_constructor include/linux/fs.h:2586 [inline]
do_sys_openat2+0xc7/0x1e0 fs/open.c:1416
do_sys_open fs/open.c:1423 [inline]
__do_sys_openat fs/open.c:1439 [inline]
__se_sys_openat fs/open.c:1434 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1434
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:
ffff88803745a480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88803745a500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803745a580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88803745a600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88803745a680: 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.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Forwarded: [PATCH] nvme: hold a controller reference while scan_work is queued or running
2026-10-02 1:22 [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvme_query_zone_info syzbot
2026-10-02 1:37 ` syzbot
@ 2026-10-02 12:58 ` syzbot
2026-10-02 16:30 ` [PATCH] nvme: keep the effects log per namespace path, not in the shared head Nguyen Ngoc Thang
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2026-10-02 12:58 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: [PATCH] nvme: hold a controller reference while scan_work is queued or running
Author: kartikey406@gmail.com
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
syzbot reported a slab-use-after-free in nvme_query_zone_info(), called
from the async namespace scan:
BUG: KASAN: slab-use-after-free in nvme_query_zone_info+0x4fd/0x6f0
Read of size 4 by task kworker/u8:13
nvme_query_zone_info
nvme_update_ns_info_block
nvme_alloc_ns
nvme_scan_ns
async_run_entry_fn
The freed object is the effects log (ctrl->cels) allocated by
nvme_get_effects_log(). It was freed by a write to the sysfs
delete_controller attribute, which dropped the last reference on the
controller via nvme_sysfs_delete() -> put_device() -> nvme_free_ctrl()
-> nvme_free_cels() while the scan was still running.
nvme_scan_work() waits for all of its async scan jobs before it
returns, so the jobs cannot outlive the work. However, nothing keeps the
controller alive while scan_work is pending or running, so the final
controller reference can be dropped underneath it and the effects log is
freed while the scan is still dereferencing it.
Take a controller reference in nvme_queue_scan() when scan_work is
queued, and drop it when nvme_scan_work() finishes. If queue_work()
reports that the work was already pending, drop the extra reference
because the pending instance already owns one. Convert the early returns
in nvme_scan_work() to a common exit so the reference is dropped on
every path.
Reported-by: syzbot+76c0f0ce8f1e846b4f84@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=76c0f0ce8f1e846b4f84
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
drivers/nvme/host/core.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index beea23d04a70..11599b0061b1 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -165,8 +165,11 @@ void nvme_queue_scan(struct nvme_ctrl *ctrl)
/*
* Only new queue scan work when admin and IO queues are both alive
*/
- if (nvme_ctrl_state(ctrl) == NVME_CTRL_LIVE && ctrl->tagset)
- queue_work(nvme_wq, &ctrl->scan_work);
+ if (nvme_ctrl_state(ctrl) == NVME_CTRL_LIVE && ctrl->tagset) {
+ nvme_get_ctrl(ctrl);
+ if (!queue_work(nvme_wq, &ctrl->scan_work))
+ nvme_put_ctrl(ctrl);
+ }
}
/*
@@ -4635,7 +4638,7 @@ static void nvme_scan_work(struct work_struct *work)
/* No tagset on a live ctrl means IO queues could not created */
if (nvme_ctrl_state(ctrl) != NVME_CTRL_LIVE || !ctrl->tagset)
- return;
+ goto out;
/*
* Identify controller limits can change at controller reset due to
@@ -4648,7 +4651,7 @@ static void nvme_scan_work(struct work_struct *work)
if (ret < 0) {
dev_warn(ctrl->device,
"reading non-mdts-limits failed: %d\n", ret);
- return;
+ goto out;
}
if (test_and_clear_bit(NVME_AER_NOTICE_NS_CHANGED, &ctrl->events)) {
@@ -4679,6 +4682,8 @@ static void nvme_scan_work(struct work_struct *work)
/* Re-read the ANA log page to not miss updates */
queue_work(nvme_wq, &ctrl->ana_work);
#endif
+out:
+ nvme_put_ctrl(ctrl);
}
/*
--
2.43.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] nvme: keep the effects log per namespace path, not in the shared head
2026-10-02 1:22 [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvme_query_zone_info syzbot
2026-10-02 1:37 ` syzbot
2026-10-02 12:58 ` Forwarded: [PATCH] nvme: hold a controller reference while scan_work is queued or running syzbot
@ 2026-10-02 16:30 ` Nguyen Ngoc Thang
2 siblings, 0 replies; 4+ messages in thread
From: Nguyen Ngoc Thang @ 2026-10-02 16:30 UTC (permalink / raw)
To: Keith Busch, Jens Axboe, Christoph Hellwig, Sagi Grimberg
Cc: Nguyen Ngoc Thang, linux-nvme, linux-kernel, Deepanshu Kartikey,
syzbot+76c0f0ce8f1e846b4f84, syzkaller-bugs, stable
nvme_alloc_ns_head() points head->effects at an effects log owned by the
controller that created the head: an entry in that controller's ctrl->cels
xarray, or ctrl->effects for the NVM command set, which also lives there.
The head is shared by all controllers attached to the same namespace and
can outlive its creator. Once that controller is deleted, nvme_free_cels()
frees the log while the head still points at it.
Any later user then reads freed memory: nvme_query_zone_info() when another
controller scans or rescans a zoned namespace, as reported by syzbot, and
nvme_command_effects() for I/O passthrough on a surviving path.
BUG: KASAN: slab-use-after-free in nvme_query_zone_info+0x4fd/0x6f0
Read of size 4 at addr ffff88803745a5f4 by task kworker/u8:13/5985
nvme_query_zone_info+0x4fd/0x6f0 drivers/nvme/host/zns.c:47
nvme_update_ns_info_block+0x1b2e/0x2af0 drivers/nvme/host/core.c:2430
nvme_update_ns_info+0xc6/0xd90 drivers/nvme/host/core.c:2553
nvme_alloc_ns+0x1a9f/0x3e50 drivers/nvme/host/core.c:4293
nvme_scan_ns+0x79d/0x910 drivers/nvme/host/core.c:4483
Freed by task 5948:
kfree+0x22b/0x6d0 mm/slub.c:6801
nvme_free_cels drivers/nvme/host/core.c:5165 [inline]
nvme_free_ctrl+0x1e4/0x6b0 drivers/nvme/host/core.c:5183
device_release+0xd2/0x270 drivers/base/core.c:2640
put_device+0x1f/0x30 drivers/base/core.c:3884
nvme_sysfs_delete+0xc9/0xf0 drivers/nvme/host/sysfs.c:500
The Commands Supported and Effects log is a per-controller property, so
store the pointer in struct nvme_ns instead and look it up for every
namespace path in nvme_init_ns_head(). Each nvme_ns holds a reference on
its controller, so the log stays valid for as long as the path exists,
and commands are checked against the log of the controller that actually
executes them. The lookup stays under subsys->lock, which already
serialized nvme_get_effects_log() for head creation.
Reproduced with two nvme-loop controllers connected to one subsystem
backed by a zoned null_blk device: delete the first controller, then
rescan the second or connect a third.
Fixes: be93e87e7802 ("nvme: support for multiple Command Sets Supported and Effects log pages")
Cc: stable@vger.kernel.org
Reported-by: syzbot+76c0f0ce8f1e846b4f84@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=76c0f0ce8f1e846b4f84
Signed-off-by: Nguyen Ngoc Thang <ngocthang2710.1999@gmail.com>
---
Tested in QEMU (x86_64, KASAN) on v7.3-rc5:
- Deterministic: two nvme-loop controllers on one subsystem backed by a
zoned null_blk, delete nvme0, rescan nvme1, connect a third. Before:
KASAN slab-use-after-free in nvme_query_zone_info() on both the rescan
and the new-controller path. After: clean.
- syzbot C reproducer, kasan_multi_shot: 175 reports before; 0 reports
in two runs after (~900 controllers created/deleted per run).
- Zone Append is still detected on every path (no "Forcing to
read-only mode"), and direct I/O to the zoned namespace works.
Deepanshu, Cc'ing you since you posted a test patch on this report.
Pinning the scanning controller in scan_work doesn't cover this case:
the freed log belongs to a different controller, the one that created
the shared head.
drivers/nvme/host/core.c | 21 +++++++++++++--------
drivers/nvme/host/nvme.h | 2 +-
drivers/nvme/host/zns.c | 2 +-
3 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index beea23d04a70..e0fea859dfaa 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1234,7 +1234,7 @@ u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns, u8 opcode)
u32 effects = 0;
if (ns) {
- effects = le32_to_cpu(ns->head->effects->iocs[opcode]);
+ effects = le32_to_cpu(ns->effects->iocs[opcode]);
if (effects & ~(NVME_CMD_EFFECTS_CSUPP | NVME_CMD_EFFECTS_LBCC))
dev_warn_once(ctrl->device,
"IO command:%02x has unusual effects:%08x\n",
@@ -4033,13 +4033,6 @@ static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ns *ns,
kref_init(&head->ref);
ns->head = head;
- if (head->ids.csi) {
- ret = nvme_get_effects_log(ctrl, head->ids.csi, &head->effects);
- if (ret)
- goto out_cleanup_srcu;
- } else
- head->effects = ctrl->effects;
-
if (ctrl->ctratt & NVME_CTRL_ATTR_FDPS) {
ret = nvme_query_fdp_info(ns, info);
if (ret < 0)
@@ -4141,6 +4134,18 @@ static int nvme_init_ns_head(struct nvme_ns *ns, struct nvme_ns_info *info)
}
mutex_lock(&ctrl->subsys->lock);
+ /*
+ * The effects log belongs to this controller, not to the shared head,
+ * which may outlive the controller that created it.
+ */
+ if (info->ids.csi) {
+ ret = nvme_get_effects_log(ctrl, info->ids.csi, &ns->effects);
+ if (ret)
+ goto out_unlock;
+ } else {
+ ns->effects = ctrl->effects;
+ }
+
head = nvme_find_ns_head(ctrl, info->nsid);
if (!head) {
ret = nvme_subsys_check_duplicate_ids(ctrl->subsys, &info->ids);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 2cff9fcbf740..7d6ced8ed78b 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -554,7 +554,6 @@ struct nvme_ns_head {
bool shared;
bool rotational;
bool passthru_err_log_enabled;
- struct nvme_effects_log *effects;
u64 nuse;
unsigned ns_id;
int instance;
@@ -620,6 +619,7 @@ struct nvme_ns {
struct list_head siblings;
struct kref kref;
struct nvme_ns_head *head;
+ struct nvme_effects_log *effects;
unsigned long flags;
#define NVME_NS_REMOVING 0
diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c
index e31ec6f4f94f..ef75448036f7 100644
--- a/drivers/nvme/host/zns.c
+++ b/drivers/nvme/host/zns.c
@@ -38,7 +38,7 @@ static int nvme_set_max_append(struct nvme_ctrl *ctrl)
int nvme_query_zone_info(struct nvme_ns *ns, unsigned lbaf,
struct nvme_zone_info *zi)
{
- struct nvme_effects_log *log = ns->head->effects;
+ struct nvme_effects_log *log = ns->effects;
struct nvme_command c = { };
struct nvme_id_ns_zns *id;
int status;
--
2.43.0
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-10-02 16:31 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-10-02 1:22 [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvme_query_zone_info syzbot
2026-10-02 1:37 ` syzbot
2026-10-02 12:58 ` Forwarded: [PATCH] nvme: hold a controller reference while scan_work is queued or running syzbot
2026-10-02 16:30 ` [PATCH] nvme: keep the effects log per namespace path, not in the shared head Nguyen Ngoc Thang
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