* [syzbot] [kernfs?] possible deadlock in array_state_store
@ 2026-10-25 4:50 syzbot
0 siblings, 0 replies; only message in thread
From: syzbot @ 2026-10-25 4:50 UTC (permalink / raw)
To: driver-core, gregkh, linux-kernel, syzkaller-bugs, tj
Hello,
syzbot found the following issue on:
HEAD commit: 3ac032ef6ca8 Merge tag 'for-linus-fwctl' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10b3aee1580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8625c9497ae83f0b
dashboard link: https://syzkaller.appspot.com/bug?extid=7657131267c5111921e2
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 (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-3ac032ef.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c8383c1d288f/vmlinux-3ac032ef.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c86b9622324/bzImage-3ac032ef.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7657131267c5111921e2@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L Y
------------------------------------------------------
syz.4.1083/10710 is trying to acquire lock:
ffff88804b6d0358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:713 [inline]
ffff88804b6d0358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: array_state_store+0x174/0xcf0 drivers/md/md.c:4705
but task is already holding lock:
ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (kn->active#77){++++}-{0:0}:
lock_acquire kernel/locking/lockdep.c:5942 [inline]
lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
kernfs_drain+0x4eb/0x600 fs/kernfs/dir.c:534
__kernfs_remove+0x34c/0xbc0 fs/kernfs/dir.c:1578
kernfs_remove_by_name_ns+0x7c/0x120 fs/kernfs/dir.c:1796
kernfs_remove_by_name include/linux/kernfs.h:644 [inline]
remove_files+0x96/0x1c0 fs/sysfs/group.c:28
sysfs_remove_group+0x8b/0x1b0 fs/sysfs/group.c:328
sysfs_remove_groups fs/sysfs/group.c:352 [inline]
sysfs_remove_groups+0x60/0xb0 fs/sysfs/group.c:344
__kobject_del+0x89/0x220 lib/kobject.c:595
kobject_cleanup lib/kobject.c:680 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x348/0x640 lib/kobject.c:737
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
process_scheduled_works kernel/workqueue.c:3578 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
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
-> #3 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}:
lock_acquire kernel/locking/lockdep.c:5942 [inline]
lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
process_one_work+0xa32/0x1b10 kernel/workqueue.c:3471
process_scheduled_works kernel/workqueue.c:3578 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
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
-> #2 ((wq_completion)md_misc){+.+.}-{0:0}:
lock_acquire kernel/locking/lockdep.c:5942 [inline]
lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
touch_wq_lockdep_map+0xad/0x1c0 kernel/workqueue.c:4272
__flush_workqueue+0x131/0x1200 kernel/workqueue.c:4314
md_alloc+0x30/0x10a0 drivers/md/md.c:6334
md_alloc_and_put drivers/md/md.c:6423 [inline]
md_probe drivers/md/md.c:6439 [inline]
md_probe+0x73/0xf0 drivers/md/md.c:6434
blk_probe_dev+0x149/0x1e0 block/genhd.c:888
blk_request_module+0x16/0xc0 block/genhd.c:901
blkdev_get_no_open+0x9b/0xf0 block/bdev.c:870
blkdev_open+0x141/0x4f0 block/fops.c:671
do_dentry_open+0x674/0x1470 fs/open.c:1000
vfs_open_consume+0xcc/0x460 fs/open.c:1131
do_open fs/namei.c:4845 [inline]
path_openat+0x1547/0x23f0 fs/namei.c:5010
do_file_open+0x20e/0x430 fs/namei.c:5039
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
-> #1 (major_names_lock){+.+.}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5942 [inline]
lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821
blk_probe_dev+0x28/0x1e0 block/genhd.c:885
blk_request_module+0x16/0xc0 block/genhd.c:901
blkdev_get_no_open+0x9b/0xf0 block/bdev.c:870
bdev_file_open_by_dev block/bdev.c:1091 [inline]
bdev_file_open_by_dev+0x70/0x210 block/bdev.c:1079
md_import_device+0x120/0x360 drivers/md/md.c:3847
md_add_new_disk+0xdbf/0x1820 drivers/md/md.c:7656
md_ioctl+0x2be7/0x36c0 drivers/md/md.c:8499
blkdev_ioctl+0x5ad/0x6f0 block/ioctl.c:798
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
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
-> #0 (&mddev->reconfig_mutex){+.+.}-{4:4}:
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
check_prevs_add kernel/locking/lockdep.c:3328 [inline]
validate_chain kernel/locking/lockdep.c:3952 [inline]
__lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
lock_acquire kernel/locking/lockdep.c:5942 [inline]
lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821
mddev_lock drivers/md/md.h:713 [inline]
array_state_store+0x174/0xcf0 drivers/md/md.c:4705
md_attr_store+0x1c5/0x330 drivers/md/md.c:6158
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
other info that might help us debug this:
Chain exists of:
&mddev->reconfig_mutex --> (work_completion)(&mddev->del_work) --> kn->active#77
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(kn->active#77);
lock((work_completion)(&mddev->del_work));
lock(kn->active#77);
lock(&mddev->reconfig_mutex);
*** DEADLOCK ***
locks held by syz.4.1083/10710: 5, last CPU#2:
#0: ffff888040588b70 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1408
#1: ffff888037ffa460 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffff888037f03908 (&of->prealloc_mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x24d/0x5f0 fs/kernfs/file.c:320
#3: ffff888037f03880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
#4: ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#4: ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337
stack backtrace:
CPU: 2 UID: 0 PID: 10710 Comm: syz.4.1083 Tainted: G L Y syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2087
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2219
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
check_prevs_add kernel/locking/lockdep.c:3328 [inline]
validate_chain kernel/locking/lockdep.c:3952 [inline]
__lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
lock_acquire kernel/locking/lockdep.c:5942 [inline]
lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821
mddev_lock drivers/md/md.h:713 [inline]
array_state_store+0x174/0xcf0 drivers/md/md.c:4705
md_attr_store+0x1c5/0x330 drivers/md/md.c:6158
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
RIP: 0033:0x7f03a8b9f559
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:00007f03a9a99028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f03a8e25fa0 RCX: 00007f03a8b9f559
RDX: 0000000000000005 RSI: 0000200000000280 RDI: 0000000000000004
RBP: 00007f03a8c36b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f03a8e26038 R14: 00007f03a8e25fa0 R15: 00007fffeac25fa8
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2026-10-25 4:50 UTC | newest]
Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-10-25 4:50 [syzbot] [kernfs?] possible deadlock in array_state_store syzbot
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox