INFO: task kworker/u8:15:3515 blocked for[ 625.973098][ T38] INFO: task kworker/u8:15:3515 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:15 state:D stack:21856 pid:3515 tgid:3515 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:3)
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2dc/0x7b0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:552
jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x75d/0x11a0 fs/fs-writeback.c:1825
writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2054
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241
wb_check_old_data_flush fs/fs-writeback.c:2345 [inline]
wb_do_writeback fs/fs-writeback.c:2398 [inline]
wb_workfn+0xb52/0xf60 fs/fs-writeback.c:2426
process_one_work kernel/workqueue.c:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:7/164:
5 locks held by kworker/u8:10/1392:
2 locks held by kworker/u8:12/1427:
4 locks held by kworker/u8:15/3515:
#0: ffff88801f29e938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff88801f29e938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc9000e12fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc9000e12fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
#2: ffff88803bab00d0 (&type->s_umount_key#73){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
#3: ffff888011a99568 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
2 locks held by udevd/5170:
2 locks held by getty/5561:
#0: ffff888036c880a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
6 locks held by kworker/1:4/5815:
2 locks held by syz-executor/10032:
4 locks held by syz.3.766/10142:
10 locks held by syz-executor/10516:
10 locks held by syz-executor/11037:
6 locks held by syz.2.1081/12380:
2 locks held by syz.5.1082/12387:
2 locks held by udevadm/12393:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5824 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:rt_mutex_owner include/linux/rtmutex.h:52 [inline]
RIP: 0010:rt_mutex_slowtrylock kernel/locking/rtmutex.c:1384 [inline]
RIP: 0010:__rt_spin_trylock kernel/locking/spinlock_rt.c:106 [inline]
RIP: 0010:rt_spin_trylock+0x37/0x2b0 kernel/locking/spinlock_rt.c:118
Code: 53 48 83 ec 10 49 89 fe 49 bc 00 00 00 00 00 fc ff df 65 4c 8b 2d d1 78 28 07 48 8d 5f 50 49 89 df 49 c1 ef 03 43 80 3c 27 00 <74> 08 48 89 df e8 3f 81 04 f7 48 8b 03 48 83 f8 01 0f 87 68 01 00
RSP: 0018:ffffc90004a8fc60 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffff8880b89459e8 RCX: 0000000000000246
RDX: dffffc0000000000 RSI: ffffffff8ba67660 RDI: ffff8880b8945998
RBP: 0000000000000001 R08: ffffffff821c57cc R09: ffffffff8df03400
R10: dffffc0000000000 R11: fffffbfff1ed4d77 R12: dffffc0000000000
R13: ffff888038e45b80 R14: ffff8880b8945998 R15: 1ffff11017128b3d
FS: 00007fce3d45c880(0000) GS:ffff888126436000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563d2e73b950 CR3: 000000005cdf6000 CR4: 00000000003526f0
Call Trace:
alloc_from_pcs mm/slub.c:4711 [inline]
slab_alloc_node mm/slub.c:4851 [inline]
kmem_cache_alloc_noprof+0x1a3/0x680 mm/slub.c:4873
fsnotify_alloc_inode_connector fs/notify/mark.c:736 [inline]
fsnotify_attach_connector_to_object fs/notify/mark.c:772 [inline]
fsnotify_add_mark_list fs/notify/mark.c:856 [inline]
fsnotify_add_mark_locked+0x638/0x12e0 fs/notify/mark.c:931
fsnotify_add_inode_mark_locked include/linux/fsnotify_backend.h:893 [inline]
inotify_new_watch fs/notify/inotify/inotify_user.c:620 [inline]
inotify_update_watch fs/notify/inotify/inotify_user.c:647 [inline]
__do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:781 [inline]
__se_sys_inotify_add_watch+0xa9d/0xf70 fs/notify/inotify/inotify_user.c:729
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fce3d5c49a7
Code: f0 ff ff 73 01 c3 48 8b 0d 4e f4 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 fe 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 21 f4 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffdb698e738 EFLAGS: 00000206 ORIG_RAX: 00000000000000fe
RAX: ffffffffffffffda RBX: 000056044d568140 RCX: 00007fce3d5c49a7
RDX: 0000000000000008 RSI: 000056044d2f12a0 RDI: 0000000000000007
RBP: 000056044d2dd910 R08: 00000000000001d0 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000206 R12: 000056044d568140
R13: 000056044d2eb190 R14: 0000000000000008 R15: 000056044d568140