INFO: task kworker/u8:10:3495 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:10 state:D stack:20264 pid:3495 tgid:3495 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 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+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:132
write_inode fs/fs-writeback.c:1525 [inline]
__writeback_single_inode+0x6f1/0x1000 fs/fs-writeback.c:1745
writeback_sb_inodes+0x6b7/0xf60 fs/fs-writeback.c:1976
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0xaf4/0xf00 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:4/73:
3 locks held by kworker/u8:7/1170:
4 locks held by kworker/u8:10/3495:
#0: ffff8881404ba938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881404ba938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000d1b7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000d1b7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888035f0a0d0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88805cf3bcc8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
1 lock held by udevd/5207:
#0: ffff8880368e6218 (&ep->lock){++++}-{3:3}, at: write_lock_irq include/linux/rwlock_rt.h:104 [inline]
#0: ffff8880368e6218 (&ep->lock){++++}-{3:3}, at: ep_poll fs/eventpoll.c:2127 [inline]
#0: ffff8880368e6218 (&ep->lock){++++}-{3:3}, at: do_epoll_wait+0x84d/0xbb0 fs/eventpoll.c:2560
2 locks held by getty/5597:
#0: ffff88823bf688a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e762e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5837:
#0: ffff88801988c238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3d/0x130 fs/kernfs/dir.c:1712
3 locks held by kworker/0:4/5908:
2 locks held by udevd/6008:
#0: ffff888034c6a488 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
#1: ffff888036a69478 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
#1: ffff888036a69478 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: lock_rename fs/namei.c:3272 [inline]
#1: ffff888036a69478 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: do_renameat2+0x3b9/0xa80 fs/namei.c:5224
2 locks held by udevd/6009:
4 locks held by syz.4.139/6733:
1 lock held by udevd/8070:
#0: ffff8880222daee8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:884 [inline]
#0: ffff8880222daee8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:848
6 locks held by udevd/8072:
3 locks held by syz.5.411/8682:
2 locks held by syz.2.412/8686:
=============================================
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 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
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: 5836 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__kasan_check_write+0x6/0x20 mm/kasan/shadow.c:37
Code: e9 ef e4 ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 89 f6 <48> 8b 0c 24 ba 01 00 00 00 e9 bc e4 ff ff 66 66 66 2e 0f 1f 84 00
RSP: 0018:ffffc90004cb7c80 EFLAGS: 00000246
RAX: 1ffff11004ade892 RBX: ffff888027a47700 RCX: ffff8880256f3b80
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8880256f3b80
RBP: ffffc90004cb7ec0 R08: ffffc90004cb7e37 R09: 0000000000000000
R10: ffffc90004cb7de0 R11: fffff52000996fc7 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff8880256f3b80 R15: ffff8880256f3b80
FS: 000055556c4ae500(0000) GS:ffff8881269c2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb1aa750000 CR3: 0000000033442000 CR4: 00000000003526f0
Call Trace:
instrument_atomic_write include/linux/instrumented.h:82 [inline]
clear_bit include/asm-generic/bitops/instrumented-atomic.h:41 [inline]
clear_ti_thread_flag include/linux/thread_info.h:102 [inline]
clear_notify_signal include/linux/sched/signal.h:347 [inline]
get_signal+0x97/0x1310 kernel/signal.c:2805
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8c06764e57
Code: 89 7c 24 10 48 89 4c 24 18 e8 45 1b 03 00 4c 8b 54 24 18 8b 54 24 14 41 89 c0 48 8b 74 24 08 8b 7c 24 10 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 10 e8 95 1b 03 00 8b 44
RSP: 002b:00007fff78a69020 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: 00000000000000d3 RBX: 00000000000000d3 RCX: 00007f8c06764e57
RDX: 0000000040000000 RSI: 00007fff78a6908c RDI: 00000000ffffffff
RBP: 00007fff78a6908c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000004f
R13: 000055556c4c1590 R14: 000000000005a763 R15: 00007fff78a690e0