[v6.6] INFO: task hung in flush_old_commits

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syzbot

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Sep 17, 2025, 4:43:35 PMSep 17
to syzkaller...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 60a9e718726f Linux 6.6.106
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15796f62580000
kernel config: https://syzkaller.appspot.com/x/.config?x=12606d4b8832c7e4
dashboard link: https://syzkaller.appspot.com/bug?extid=3d9612c74eb59c731268
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eca27e056a5a/disk-60a9e718.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bc64d4eeb7f6/vmlinux-60a9e718.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a345041561ac/bzImage-60a9e718.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3d9612...@syzkaller.appspotmail.com

INFO: task kworker/0:5:5892 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:5 state:D stack:24808 pid:5892 ppid:2 flags:0x00004000
Workqueue: events_long flush_old_commits
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
reiserfs_sync_fs fs/reiserfs/super.c:76 [inline]
flush_old_commits+0x1e2/0x2f0 fs/reiserfs/super.c:111
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>

Showing all locks held in the system:
3 locks held by kworker/u4:0/11:
2 locks held by kworker/1:1/27:
#0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90000a2fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90000a2fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
1 lock held by khungtaskd/29:
#0: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/u4:2/42:
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90000b2fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90000b2fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
2 locks held by kworker/u4:3/48:
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90000b8fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90000b8fd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
2 locks held by kworker/u4:4/59:
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc900015a7d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc900015a7d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
2 locks held by kworker/u4:5/60:
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffff8880b8f289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
#1: ffff8880b8f289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x20ee/0x44d0 kernel/sched/core.c:6694
5 locks held by kworker/u4:7/1082:
#0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000462fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000462fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffffffff8dfafad0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x136/0xb90 net/core/net_namespace.c:606
#3: ffffffff8dfbc908 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe9/0xa60 net/core/dev.c:11606
#4: ffffffff8cd35df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
#4: ffffffff8cd35df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004
3 locks held by kworker/u4:8/1091:
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000454fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000454fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffffffff8dfbc908 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286
2 locks held by getty/5546:
#0: ffff88803113a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
3 locks held by kworker/1:4/5833:
#0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000470fd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000470fd00 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffffffff8dfbc908 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
4 locks held by kworker/0:5/5892:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90002f47d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90002f47d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff888079ea20e0 (&type->s_umount_key#26){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88802ffa1090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
3 locks held by syz.0.110/6502:
1 lock held by syz.7.361/7881:
#0: ffffffff8dfbc908 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3b9/0x1fd0 drivers/net/tun.c:3121
1 lock held by syz.7.361/7884:
#0: ffffffff8dfbc908 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
#0: ffffffff8dfbc908 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6472
2 locks held by syz.8.364/7893:
#0: ffff8880572fb220 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#0: ffff8880572fb220 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline]
#0: ffff8880572fb220 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x9b/0x230 net/socket.c:1421
#1: ffffffff8cd35df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
#1: ffffffff8cd35df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x830 kernel/rcu/tree_exp.h:1004

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf41/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: kworker/1:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events free_obj_work
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x60 kernel/kcov.c:216
Code: 48 8b 3d dc 06 c5 0c 48 89 de 5b e9 73 7a 56 00 cc cc cc f3 0f 1e fa 48 8b 04 24 65 48 8b 0d b0 29 7e 7e 65 8b 15 b1 29 7e 7e <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00
RSP: 0018:ffffc90000a2f570 EFLAGS: 00000246
RAX: ffffffff813aab13 RBX: ffffffff8ece8bfa RCX: ffff88801c643c00
RDX: 0000000080000001 RSI: ffffffff8cb9e760 RDI: 0000000000000005
RBP: ffffc90000a2f698 R08: ffff88801c643c00 R09: 0000000000000008
R10: 0000000000000009 R11: 0000000000000000 R12: ffffc90000a2f648
R13: dffffc0000000000 R14: 0000000000000005 R15: ffffffff8ece8bfe
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f48b95b6e9c CR3: 00000000257c6000 CR4: 00000000003506e0
Call Trace:
<TASK>
unwind_next_frame+0x853/0x2970 arch/x86/kernel/unwind_orc.c:517
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
kmem_cache_free+0xf8/0x280 mm/slub.c:3852
free_obj_work+0x414/0x580 lib/debugobjects.c:332
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>


---
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup

syzbot

unread,
Dec 13, 2025, 1:03:26 AM (6 days ago) Dec 13
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: 5fa4793a2d2d Linux 6.6.119
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11a4b592580000
kernel config: https://syzkaller.appspot.com/x/.config?x=691a6769a86ac817
dashboard link: https://syzkaller.appspot.com/bug?extid=3d9612c74eb59c731268
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=107171c2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/63699875f1dd/disk-5fa4793a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8506652fcb6f/vmlinux-5fa4793a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1b30ceed1710/bzImage-5fa4793a.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/23928b038abe/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=11b43e1a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3d9612...@syzkaller.appspotmail.com

INFO: task kworker/1:5:6373 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:5 state:D stack:25768 pid:6373 ppid:2 flags:0x00004000
Workqueue: events_long flush_old_commits
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
reiserfs_sync_fs fs/reiserfs/super.c:76 [inline]
flush_old_commits+0x1e2/0x2f0 fs/reiserfs/super.c:111
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
INFO: task syz.0.162:6917 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.162 state:D stack:23400 pid:6917 ppid:5931 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
reiserfs_write_lock_nested+0x60/0xd0 fs/reiserfs/lock.c:78
reiserfs_cond_resched fs/reiserfs/reiserfs.h:848 [inline]
reiserfs_update_sd_size+0x3d7/0xe20 fs/reiserfs/inode.c:1488
reiserfs_update_sd fs/reiserfs/reiserfs.h:3098 [inline]
indirect2direct+0x5d2/0x9c0 fs/reiserfs/tail_conversion.c:299
maybe_indirect_to_direct fs/reiserfs/stree.c:1585 [inline]
reiserfs_cut_from_item+0x78b/0x1f10 fs/reiserfs/stree.c:1692
reiserfs_do_truncate+0xa3d/0x1340 fs/reiserfs/stree.c:1971
reiserfs_truncate_file+0x37a/0x7c0 fs/reiserfs/inode.c:2306
reiserfs_file_release+0x8e4/0xa50 fs/reiserfs/file.c:109
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1ce/0x250 kernel/task_work.c:239
get_signal+0x1235/0x1400 kernel/signal.c:2678
arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6f8b18f749
RSP: 002b:00007f6f8a7bc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: 0000000000000012 RBX: 00007f6f8b3e6180 RCX: 00007f6f8b18f749
RDX: 0000000000000012 RSI: 00002000000002c0 RDI: 0000000000000006
RBP: 00007f6f8b213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6f8b3e6218 R14: 00007f6f8b3e6180 R15: 00007ffde413d7a8
</TASK>
INFO: task syz.0.162:6918 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.162 state:D stack:26472 pid:6918 ppid:5931 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
io_schedule+0x80/0xd0 kernel/sched/core.c:9022
folio_wait_bit_common+0x6eb/0xf70 mm/filemap.c:1329
__filemap_get_folio+0xbc/0xbc0 mm/filemap.c:1910
pagecache_get_page+0x2a/0x250 mm/folio-compat.c:99
find_or_create_page include/linux/pagemap.h:755 [inline]
grab_cache_page include/linux/pagemap.h:877 [inline]
convert_tail_for_hole fs/reiserfs/inode.c:592 [inline]
reiserfs_get_block+0x2c6e/0x3ed0 fs/reiserfs/inode.c:921
__block_write_begin_int+0x566/0x1ad0 fs/buffer.c:2124
reiserfs_write_begin+0x20a/0x4c0 fs/reiserfs/inode.c:2771
generic_cont_expand_simple+0x13a/0x200 fs/buffer.c:2482
reiserfs_setattr+0x58f/0x11a0 fs/reiserfs/inode.c:3302
notify_change+0xb0d/0xe10 fs/attr.c:499
do_truncate+0x19b/0x220 fs/open.c:66
vfs_truncate+0x266/0x300 fs/open.c:112
do_sys_truncate+0xe0/0x1a0 fs/open.c:135
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6f8b18f749
RSP: 002b:00007f6f8a79b038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f6f8b3e6270 RCX: 00007f6f8b18f749
RDX: 0000000000000000 RSI: 00000000003a6000 RDI: 0000200000000080
RBP: 00007f6f8b213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6f8b3e6308 R14: 00007f6f8b3e6270 R15: 00007ffde413d7a8
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
4 locks held by kworker/u4:3/49:
3 locks held by kworker/0:2/172:
#0: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558
#1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
#1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x20ee/0x44d0 kernel/sched/core.c:6694
#2: ffff8880b8e43c18 (&ACCESS_PRIVATE(sdp, lock)){....}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:376 [inline]
#2: ffff8880b8e43c18 (&ACCESS_PRIVATE(sdp, lock)){....}-{2:2}, at: srcu_invoke_callbacks+0x302/0x440 kernel/rcu/srcutree.c:1749
2 locks held by getty/5528:
#0: ffff8880312c20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by syz-executor/5941:
#0: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
#0: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x830 kernel/rcu/tree_exp.h:1004
2 locks held by kworker/0:4/5982:
#0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc900039f7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc900039f7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
4 locks held by kworker/1:5/6373:
#0:
ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000b92fd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000b92fd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff8880259600e0 (&type->s_umount_key#26){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88806d04d090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
2 locks held by syz.0.162/6917:
#0: ffff888076ea6ab8 (&ei->tailpack){+.+.}-{3:3}, at: reiserfs_file_release+0xc3/0xa50 fs/reiserfs/file.c:41
#1: ffff88806d04d090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock_nested+0x60/0xd0 fs/reiserfs/lock.c:78
3 locks held by syz.0.162/6918:
#0: ffff888025960418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff888076ea6cf0 (&sb->s_type->i_mutex_key#20){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#1: ffff888076ea6cf0 (&sb->s_type->i_mutex_key#20){+.+.}-{3:3}, at: do_truncate+0x187/0x220 fs/open.c:64
#2: ffff88806d04d090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock_nested+0x60/0xd0 fs/reiserfs/lock.c:78
2 locks held by udevd/6989:
1 lock held by syz.1.389/8246:
#0: ffff88807cb5d720 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:124 [inline]
#0: ffff88807cb5d720 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x168/0x400 mm/util.c:554
3 locks held by syz.1.389/8247:
1 lock held by syz.2.387/8249:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf41/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6837 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:kasan_check_range+0x1c0/0x290 mm/kasan/generic.c:-1
Code: 49 8d 5c 24 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 12 41 80 3b 00 0f 85 a6 00 00 00 49 ff c3 49 ff cc 75 ee 5b 41 5c <41> 5d 41 5e 41 5f 5d c3 45 84 ff 75 61 41 f7 c7 00 ff 00 00 75 5d
RSP: 0018:ffffc90005597758 EFLAGS: 00000056
RAX: 0000000000000101 RBX: ffff8880197eda00 RCX: ffffffff8167b5a4
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90d94610
RBP: 0000000000000006 R08: ffffffff90d94617 R09: 1ffffffff21b28c2
R10: dffffc0000000000 R11: fffffbfff21b28c3 R12: 0000000000000040
R13: dffffc0000000000 R14: fffffbfff21b28c3 R15: 1ffffffff21b28c2
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f277022a000 CR3: 000000002df36000 CR4: 00000000003506f0
Call Trace:
<TASK>
instrument_atomic_read include/linux/instrumented.h:68 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
hlock_class kernel/locking/lockdep.c:228 [inline]
mark_lock+0x94/0x320 kernel/locking/lockdep.c:4656
mark_held_locks kernel/locking/lockdep.c:4274 [inline]
__trace_hardirqs_on_caller kernel/locking/lockdep.c:4300 [inline]
lockdep_hardirqs_on_prepare+0x369/0x760 kernel/locking/lockdep.c:4359
trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:61
crng_make_state+0x349/0x700 drivers/char/random.c:372
_get_random_bytes+0xd6/0x210 drivers/char/random.c:385
eth_random_addr include/linux/etherdevice.h:232 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:755 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
nsim_dev_trap_report_work+0x338/0xb00 drivers/net/netdevsim/dev.c:851
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>


---
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.

syzbot

unread,
Dec 17, 2025, 5:16:35 PM (2 days ago) Dec 17
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: 5fa4793a2d2d Linux 6.6.119
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=148a631a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=691a6769a86ac817
dashboard link: https://syzkaller.appspot.com/bug?extid=3d9612c74eb59c731268
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14130d58580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1505b184580000

Downloadable assets:
mounted in repro: https://storage.googleapis.com/syzbot-assets/e1d444a9d06d/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=16ec977c580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3d9612...@syzkaller.appspotmail.com

INFO: task kworker/1:3:5785 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:3 state:D stack:23440 pid:5785 ppid:2 flags:0x00004000
Workqueue: events_long flush_old_commits
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
reiserfs_sync_fs fs/reiserfs/super.c:76 [inline]
flush_old_commits+0x1e2/0x2f0 fs/reiserfs/super.c:111
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>

Showing all locks held in the system:
4 locks held by kworker/0:0/8:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc900000d7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc900000d7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff8880302320e0 (&type->s_umount_key#25){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88802f395090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
1 lock held by khungtaskd/29:
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/u4:9/3498:
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000cc57d00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000cc57d00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
2 locks held by getty/5526:
#0: ffff88814ded00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
4 locks held by kworker/1:3/5785:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90002e47d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90002e47d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff8880791500e0 (&type->s_umount_key#25){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88802b5c7090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/1:4/5786:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000461fd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000461fd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff888024c9c0e0 (&type->s_umount_key#25){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88805fcaf090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/0:4/5835:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc900032a7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc900032a7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff8880242960e0 (&type->s_umount_key#25){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff888061d44090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
3 locks held by syz.0.17/5924:
3 locks held by syz.1.18/5950:
4 locks held by kworker/1:5/5981:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc900036e7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc900036e7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff8880605da0e0 (&type->s_umount_key#25){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88806e97b090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
3 locks held by syz.2.19/5982:
3 locks held by syz.3.20/6005:
4 locks held by kworker/1:6/6007:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90003887d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90003887d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff88805efd00e0 (&type->s_umount_key#25){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88805ed53090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
3 locks held by syz.4.21/6034:
4 locks held by kworker/0:5/6070:
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90003b77d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90003b77d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffff88802c8ba0e0 (&type->s_umount_key#25){++++}-{3:3}, at: flush_old_commits+0xcc/0x2f0 fs/reiserfs/super.c:97
#3: ffff88802506d090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
3 locks held by syz.5.22/6073:
3 locks held by syz.6.23/6104:
3 locks held by syz.7.24/6142:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf41/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6142 Comm: syz.7.24 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x10/0x90 kernel/kcov.c:313
Code: 11 10 48 89 74 11 18 48 89 44 11 20 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 40 21 7e 7e <65> 8b 0d 41 21 7e 7e 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75
RSP: 0018:ffffc9000478ea38 EFLAGS: 00000282
RAX: ffffffff82225e7a RBX: 00000000ffffffff RCX: 0000000000000000
RDX: ffff88801b361e00 RSI: 00000000ffffffff RDI: 00000000ffffffff
RBP: ffffc9000478eb80 R08: 0000000000000000 R09: 00000000ffffffff
R10: 00000000ffffffff R11: 0000000000000000 R12: ffff888060730080
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000002
FS: 000055557ba7e500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557ba995c8 CR3: 0000000027eb2000 CR4: 00000000003506f0
Call Trace:
<TASK>
get_num_ver+0x62a/0xfe0 fs/reiserfs/fix_node.c:521
ip_check_balance fs/reiserfs/fix_node.c:1523 [inline]
check_balance fs/reiserfs/fix_node.c:2083 [inline]
fix_nodes+0x2854/0x82e0 fs/reiserfs/fix_node.c:2636
reiserfs_paste_into_item+0x5ce/0x7f0 fs/reiserfs/stree.c:2128
reiserfs_get_block+0x1bd3/0x3ed0 fs/reiserfs/inode.c:1069
__block_write_begin_int+0x566/0x1ad0 fs/buffer.c:2124
reiserfs_write_begin+0x20a/0x4c0 fs/reiserfs/inode.c:2771
generic_cont_expand_simple+0x13a/0x200 fs/buffer.c:2482
reiserfs_setattr+0x58f/0x11a0 fs/reiserfs/inode.c:3302
notify_change+0xb0d/0xe10 fs/attr.c:499
do_truncate+0x19b/0x220 fs/open.c:66
vfs_truncate+0x266/0x300 fs/open.c:112
do_sys_truncate+0xe0/0x1a0 fs/open.c:135
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5adeb8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe86b5e488 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f5adede5fa0 RCX: 00007f5adeb8f749
RDX: 0000000000000000 RSI: 000000000800088a RDI: 0000200000000000
RBP: 00007f5adec13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5adede5fa0 R14: 00007f5adede5fa0 R15: 0000000000000002
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