INFO: task kworker/0:6:1283 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:6     state:D stack:13616 pid:1283  ppid:2      flags:0x00004000
Workqueue: events_long flush_old_commits

Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x589/0x10a0 kernel/sched/core.c:6562
 schedule+0x50/0xb0 kernel/sched/core.c:6638
 schedule_preempt_disabled+0x2e/0x40 kernel/sched/core.c:6697
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x44c/0x9b0 kernel/locking/mutex.c:747
 reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
 reiserfs_sync_fs fs/reiserfs/super.c:76 [inline]
 flush_old_commits+0xbf/0x160 fs/reiserfs/super.c:111
 process_one_work+0x27d/0x4c0 kernel/workqueue.c:2292
 worker_thread+0x236/0x3a0 kernel/workqueue.c:2439
 kthread+0xcc/0xe0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: task syz-executor:2657 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:12080 pid:2657  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x589/0x10a0 kernel/sched/core.c:6562
 schedule+0x50/0xb0 kernel/sched/core.c:6638
 schedule_preempt_disabled+0x2e/0x40 kernel/sched/core.c:6697
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x44c/0x9b0 kernel/locking/mutex.c:747
 reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
 reiserfs_readdir_inode+0x20b/0x6b0 fs/reiserfs/dir.c:79
 iterate_dir+0xa6/0x180 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x64/0xf0 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f93253c20b3
RSP: 002b:00007fffd0c43bb8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 000055557bf014e0 RCX: 00007f93253c20b3
RDX: 0000000000008000 RSI: 000055557bf014e0 RDI: 0000000000000005
RBP: 000055557bf014b4 R08: 0000000000028b61 R09: 0000000000000000
R10: 00007f93255bacc0 R11: 0000000000000293 R12: ffffffffffffffa8
R13: 0000000000000010 R14: 000055557bf014b0 R15: 00007fffd0c45e70
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/0:0/7:
 #0: 
ffff888100062938
 (
(wq_completion)events_long
){....}-{0:0}
, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #1: ffffc9000008be68 ((work_completion)(&(&sbi->old_work)->work)){....}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #2: ffff888142e6f0e0 (&type->s_umount_key#44){....}-{3:3}, at: flush_old_commits+0x37/0x160 fs/reiserfs/super.c:97
 #3: ffff888105fe1890 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
1 lock held by rcu_tasks_kthre/12:
 #0: 
ffffffff83572068
 (rcu_tasks.tasks_gp_mutex){....}-{3:3}, at: rcu_tasks_one_gp kernel/rcu/tasks.h:517 [inline]
 (rcu_tasks.tasks_gp_mutex){....}-{3:3}, at: rcu_tasks_kthread+0x97/0x4c0 kernel/rcu/tasks.h:562
1 lock held by khungtaskd/27:
 #0: 
ffffffff83571e28
 (
rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x2a/0xf0 kernel/locking/lockdep.c:6513
2 locks held by getty/1146:
 #0: 
ffff888101fa5098
 (
&tty->ldisc_sem
){....}-{0:0}
, at: tty_ldisc_ref_wait+0x1c/0x40 drivers/tty/tty_ldisc.c:244
 #1: ffffc90000bfb2f0 (&ldata->atomic_read_lock){....}-{3:3}, at: n_tty_read+0x19e/0x6d0 drivers/tty/n_tty.c:2198
4 locks held by kworker/0:3/1219:
 #0: 
ffff888100062938
 ((wq_completion)events_long){....}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #1: ffffc90001ed3e68 ((work_completion)(&(&sbi->old_work)->work)){....}-{0:0}
, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #2: ffff888100d770e0 (&type->s_umount_key
#44
){....}-{3:3}
, at: flush_old_commits+0x37/0x160 fs/reiserfs/super.c:97
 #3: ffff88811c729090 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
4 locks held by kworker/0:6/1283:
 #0: ffff888100062938 ((wq_completion)events_long){....}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #1: 
ffffc90001ff3e68 ((work_completion)(&(&sbi->old_work)->work)){....}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #2: ffff888100d720e0 (&type->s_umount_key#44){....}-{3:3}, at: flush_old_commits+0x37/0x160 fs/reiserfs/super.c:97
 #3: ffff888112288890 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
4 locks held by kworker/1:8/2649:
 #0: 
ffff888100062938
 ((wq_completion)events_long){....}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #1: 
ffffc90001f13e68
 (
(work_completion)(&(&sbi->old_work)->work)
){....}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #2: ffff8881452520e0 (&type->s_umount_key#44){....}-{3:3}, at: flush_old_commits+0x37/0x160 fs/reiserfs/super.c:97
 #3: ffff88811228a090 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
2 locks held by kworker/1:10/2652:
 #0: 
ffff888100063138
 (
(wq_completion)rcu_gp
){....}-{0:0}
, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
 #1: 
ffffc90001f2be68 ((work_completion)(&rew->rew_work)){....}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267
3 locks held by syz-executor/2657:
 #0: 
ffff888103e6aae8
 (
&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038
 #1: ffff88810f5302e0 (&type->i_mutex_dir_key
#8
){....}-{3:3}
, at: iterate_dir+0x40/0x180 fs/readdir.c:55
 #2: ffff888112288890
 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
3 locks held by syz.3.17/3071:
3 locks held by syz-executor/3073:
 #0: 
ffff888100ed42e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038
 #1: ffff88810f530f10 (
&type->i_mutex_dir_key
#8
){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55
 #2: 
ffff88811228a090
 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
3 locks held by syz.4.19/3488:
3 locks held by syz-executor/3907:
 #0: 
ffff888101f272e8
 (
&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038
 #1: 
ffff88810f531b40 (&type->i_mutex_dir_key#8){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55
 #2: 
ffff888105fe1890 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
3 locks held by syz.6.25/4322:
3 locks held by syz-executor/4324:
 #0: ffff88810834fce8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038
 #1: ffff88810f5b9b40 (&type->i_mutex_dir_key#8){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55
 #2: ffff88811c729090 (&sbi->lock){....}-{3:3}, at: reiserfs_write_lock+0x26/0x40 fs/reiserfs/lock.c:27
5 locks held by syz.7.26/4739:
1 lock held by syz-executor/4741:
 #0: ffffffff83572e78 (rcu_state.exp_mutex){....}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #0: ffffffff83572e78 (rcu_state.exp_mutex){....}-{3:3}, at: synchronize_rcu_expedited+0x298/0x750 kernel/rcu/tree_exp.h:962

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 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+0x74/0xbb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x102/0x160 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0xa5/0x160 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0x533/0x560 kernel/hung_task.c:377
 kthread+0xcc/0xe0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4739 Comm: syz.7.26 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:io_serial_in+0xf/0x20 drivers/tty/serial/8250/8250_port.c:461
Code: 00 00 d3 e6 48 63 f6 48 03 77 48 89 d7 e9 f9 7a e8 ff 66 0f 1f 84 00 00 00 00 00 89 f2 0f b6 8f f1 00 00 00 d3 e2 03 57 40 ec <0f> b6 c0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 0f b6 8f f1 00
RSP: 0018:ffffc90004c27148 EFLAGS: 00000006
RAX: 0000000000000005 RBX: ffffffff8814f440 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000001 RDI: ffffffff8814f440
RBP: ffffffff87f74b80 R08: 0000000000000000 R09: 0000000000000005
R10: 0000000052455349 R11: 0000000053494552 R12: 000000000000009e
R13: ffffc90004c27317 R14: ffffffff8364ae30 R15: 0000000000000000
FS:  00007f0831d046c0(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f855dafb000 CR3: 000000011dccf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial_port_in include/linux/serial_core.h:668 [inline]
 serial8250_console_write+0xb6/0x630 drivers/tty/serial/8250/8250_port.c:3437
 call_console_driver kernel/printk/printk.c:1977 [inline]
 console_emit_next_record+0x43b/0x550 kernel/printk/printk.c:2777
 console_flush_all kernel/printk/printk.c:-1 [inline]
 console_unlock+0x14e/0x280 kernel/printk/printk.c:2906
 vprintk_emit+0xe0/0x3a0 kernel/printk/printk.c:2303
 _printk+0x54/0x70 kernel/printk/printk.c:2328
 __reiserfs_warning+0xd4/0x100 fs/reiserfs/prints.c:290
 reiserfs_read_bitmap_block+0x159/0x180 fs/reiserfs/bitmap.c:1434
 scan_bitmap_block+0x74/0x380 fs/reiserfs/bitmap.c:164
 scan_bitmap fs/reiserfs/bitmap.c:402 [inline]
 allocate_without_wrapping_disk fs/reiserfs/bitmap.c:1161 [inline]
 blocknrs_and_prealloc_arrays_from_search_start fs/reiserfs/bitmap.c:1274 [inline]
 reiserfs_allocate_blocknrs+0x66b/0xea0 fs/reiserfs/bitmap.c:1375
 _allocate_block fs/reiserfs/inode.c:-1 [inline]
 reiserfs_get_block+0xad2/0x12a0 fs/reiserfs/inode.c:756
 __block_write_begin_int+0x186/0x6a0 fs/buffer.c:1991
 reiserfs_write_begin+0x109/0x220 fs/reiserfs/inode.c:2775
 generic_perform_write+0xa0/0x220 mm/filemap.c:3862
 __generic_file_write_iter+0x6f/0xb0 mm/filemap.c:3960
 generic_file_write_iter+0x43/0xb0 mm/filemap.c:3989
 __kernel_write_iter+0xc2/0x1b0 fs/read_write.c:517
 __kernel_write+0x8c/0xb0 fs/read_write.c:537
 __dump_emit fs/coredump.c:873 [inline]
 dump_emit+0x91/0xf0 fs/coredump.c:910
 elf_core_dump+0xd74/0x1130 fs/binfmt_elf.c:2306
 do_coredump+0xa02/0xde0 fs/coredump.c:824
 get_signal+0x603/0x750 kernel/signal.c:2857
 arch_do_signal_or_restart+0x92/0x630 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x6b/0xd0 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0x91/0xd0 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x20 kernel/entry/common.c:316
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f0830d8f751
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:fffffffffffffe80 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f0830fe5fa0 RCX: 00007f0830d8f749
RDX: 0000000000000000 RSI: fffffffffffffe80 RDI: 0000000000008000
RBP: 00007f0830e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f0830fe6038 R14: 00007f0830fe5fa0 R15: 00007fff7771fad8
 </TASK>