syzbot

INFO: task kworker/1:3:4198 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:22624 pid: 4198 ppid:     2 flags:0x00004000
Workqueue: events_long flush_old_commits
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
 reiserfs_sync_fs fs/reiserfs/super.c:76 [inline]
 flush_old_commits+0x1de/0x2f0 fs/reiserfs/super.c:111
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/0:0/7:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90000cc7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88807e4f60e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88807e90e090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/1:0/21:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90000db7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff8880598460e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88805997b090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/1:1/23:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90000ddfd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88805da480e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88801d468090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by kworker/u4:1/144:
4 locks held by kworker/1:2/1107:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90004bf7d00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff888023eaa0e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88805d34e090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
2 locks held by getty/3949:
 #0: ffff88814d4c9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
4 locks held by kworker/1:3/4198:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002effd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff888079fba0e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88807a2c0090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
2 locks held by kworker/0:4/4238:
 #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000340fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
4 locks held by kworker/0:6/4266:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002fbfd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88805a0e00e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff888025bcb090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/0:7/4267:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002fafd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff8880261660e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88807b69f090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
4 locks held by kworker/0:8/4269:
 #0: ffff888016871138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000348fd00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88802616c0e0 (&type->s_umount_key#53){.+.+}-{3:3}, at: flush_old_commits+0xc8/0x2f0 fs/reiserfs/super.c:97
 #3: ffff88802749e090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
5 locks held by syz.0.17/4441:
3 locks held by syz.1.18/4521:
3 locks held by syz.2.19/4551:
3 locks held by syz.3.20/4576:
3 locks held by syz.4.21/4604:
3 locks held by syz.5.22/4639:
3 locks held by syz.6.23/4669:
3 locks held by syz.7.24/4697:
2 locks held by dhcpcd/4702:
 #0: ffff888025be8120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1731 [inline]
 #0: ffff888025be8120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xce0 net/packet/af_packet.c:3212
 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by dhcpcd/4703:
 #0: ffff888024836120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1731 [inline]
 #0: ffff888024836120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xce0 net/packet/af_packet.c:3212
 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
1 lock held by dhcpcd/4704:
 #0: ffff8880276ca120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1731 [inline]
 #0: ffff8880276ca120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xce0 net/packet/af_packet.c:3212

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

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+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4441 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:205
Code: 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d d0 6b f1 0b 48 89 de 5b e9 d7 9e 43 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900032eea20 EFLAGS: 00000246
RAX: ffffffff81ffb3d1 RBX: ffff8880796bc080 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8880796bc080
RBP: 0000000000000001 R08: 0000000000000000 R09: 00000000ffffffff
R10: 00000000ffffffff R11: 0000000000000000 R12: ffff8880796bc080
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00005555909bf500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a36adf8660 CR3: 000000005be5c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 direntry_part_size+0x21/0x1a0 fs/reiserfs/item_ops.c:581
 get_num_ver+0x4a3/0xfd0 fs/reiserfs/fix_node.c:475
 ip_check_balance fs/reiserfs/fix_node.c:1523 [inline]
 check_balance fs/reiserfs/fix_node.c:2083 [inline]
 fix_nodes+0x2867/0x82d0 fs/reiserfs/fix_node.c:2635
 reiserfs_paste_into_item+0x5c8/0x7e0 fs/reiserfs/stree.c:2130
 reiserfs_get_block+0x1bde/0x4100 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012
 reiserfs_write_begin+0x34b/0x810 fs/reiserfs/inode.c:2790
 generic_cont_expand_simple+0xe9/0x190 fs/buffer.c:2362
 reiserfs_setattr+0x42f/0x1010 fs/reiserfs/inode.c:3319
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xdc/0x190 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb1324ad749
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:00007ffe557cf2b8 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007fb132703fa0 RCX: 00007fb1324ad749
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00002000000000c0
RBP: 00007fb132531f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb132703fa0 R14: 00007fb132703fa0 R15: 0000000000000002
 </TASK>