INFO: task kworker/u8:11:1575 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:11 state:D stack:20264 pid:1575 tgid:1575 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
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+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 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:
4 locks held by kworker/u8:1/13:
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888021b8c0d0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88803d8b0bb8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
1 lock held by khungtaskd/38:
#0: ffffffff8d9a8dc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8dc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8dc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:5/148:
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90003a7fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90003a7fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888053dc40d0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff8880566cda38 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
4 locks held by kworker/u8:6/1383:
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000592fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000592fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff88803559a0d0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff8880566c9588 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
4 locks held by kworker/u8:10/1467:
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90005b5fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90005b5fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff88803b2a80d0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff888056624698 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
4 locks held by kworker/u8:11/1575:
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90005d0fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90005d0fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888034a880d0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff8880565c2928 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
2 locks held by getty/5603:
#0: ffff88823bf380a0 (&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
4 locks held by syz.0.17/6078:
4 locks held by syz.1.18/6105:
4 locks held by kworker/u8:0/6134:
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000422fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000422fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff88802446c0d0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff8880565c6408 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
4 locks held by syz.2.19/6135:
4 locks held by syz.3.20/6161:
4 locks held by syz.4.21/6191:
4 locks held by syz.5.22/6227:
4 locks held by kworker/u8:4/6228:
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8881432ea138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000406fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000406fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888056c300d0 (&type->s_umount_key#54){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff88803d8b5068 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
2 locks held by kworker/u8:7/6230:
4 locks held by syz.6.23/6260:
4 locks held by syz.7.24/6296:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6260 Comm: syz.6.23 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x2b/0xa0 kernel/kcov.c:300
Code: 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 40 f6 91 65 44 8b 05 07 d1 37 10 41 81 e0 00 00 ff 00 ba 00 01 00 00 23 91 0c 0b 00 00 <41> 89 d1 45 09 c1 74 12 45 85 c0 75 5f 85 d2 74 5b 83 b9 d4 15 00
RSP: 0018:ffffc900046df6a0 EFLAGS: 00000246
RAX: ffffffff833621f5 RBX: 0000000000000004 RCX: ffff8880341b3b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000ff
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880363d9000 R14: 0000000000000000 R15: 1ffff11006c7b202
FS: 0000555577295500(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b563092a38 CR3: 0000000054b36000 CR4: 00000000003526f0
Call Trace:
dtSplitRoot+0x775/0x16c0 fs/jfs/jfs_dtree.c:1979
dtSplitUp fs/jfs/jfs_dtree.c:993 [inline]
dtInsert+0xef8/0x5f40 fs/jfs/jfs_dtree.c:871
jfs_symlink+0x715/0xe60 fs/jfs/namei.c:1020
vfs_symlink+0x143/0x2f0 fs/namei.c:4730
do_symlinkat+0x1b1/0x3f0 fs/namei.c:4756
__do_sys_symlink fs/namei.c:4777 [inline]
__se_sys_symlink fs/namei.c:4775 [inline]
__x64_sys_symlink+0x7a/0x90 fs/namei.c:4775
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffb1843eec9
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:00007ffcc3558408 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007ffb18695fa0 RCX: 00007ffb1843eec9
RDX: 0000000000000000 RSI: 0000200000000800 RDI: 0000200000000540
RBP: 00007ffb184c1f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb18695fa0 R14: 00007ffb18695fa0 R15: 0000000000000002