INFO: task kworker/u8:4:69 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4 state:D stack:21504 pid:69 tgid:69 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:2)
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:1813
writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2042
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2229
wb_check_old_data_flush fs/fs-writeback.c:2333 [inline]
wb_do_writeback fs/fs-writeback.c:2386 [inline]
wb_workfn+0xb52/0xf60 fs/fs-writeback.c:2414
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
INFO: task syz.7.162:7045 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.162 state:D stack:25120 pid:7045 tgid:7044 ppid:6442 task_flags:0x400140 flags:0x00080002
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]
schedule+0x164/0x360 kernel/sched/core.c:7008
wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227
sync_inodes_sb+0x1e1/0xc10 fs/fs-writeback.c:2924
__iterate_supers+0x13d/0x290 fs/super.c:927
ksys_sync fs/sync.c:102 [inline]
__ia32_sys_sync+0xa0/0x120 fs/sync.c:111
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: 0033:0x7f287de6c799
RSP: 002b:00007f287c0c6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f287e0e5fa0 RCX: 00007f287de6c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f287e0e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f287e0e6038 R14: 00007f287e0e5fa0 R15: 00007ffcf80ae0c8
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcb980 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:4/69:
#0: ffff88801aabc138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff88801aabc138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc9000154fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc9000154fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
#2: ffff8880367a20d0 (&type->s_umount_key#61){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
#3: ffff88803e2d01e8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
2 locks held by getty/5555:
#0: ffff888037a5f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/6155:
5 locks held by syz-executor/6259:
4 locks held by syz.2.100/6540:
2 locks held by syz.7.162/7045:
#0: ffff8880367a20d0 (&type->s_umount_key#61){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff8880367a20d0 (&type->s_umount_key#61){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
#1: ffff888025c8c8c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:398 [inline]
#1: ffff888025c8c8c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1c5/0xc10 fs/fs-writeback.c:2922
1 lock held by syz.1.418/9316:
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: free_one_page+0x43/0x250 mm/page_alloc.c:1585
3 locks held by syz.9.423/9336:
1 lock held by dhcpcd-run-hook/9342:
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff88813fffc5d8 (&zone->lock){+.+.}-{3:3}, at: free_one_page+0x43/0x250 mm/page_alloc.c:1585
=============================================
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 02/12/2026
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: 5163 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:mark_lock+0x18/0x190 kernel/locking/lockdep.c:4722
Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 8b 46 20 89 c1 81 e1 00 00 03 00 83 f9 01 09 00 00 00 83 db 00 83 fa 08 0f 45 da bd 01 00 00 00 89 d9 d3
RSP: 0018:ffffc900051475a8 EFLAGS: 00000016
RAX: 00000000000500be RBX: ffff888039f55b80 RCX: 0000000000010000
RDX: 0000000000000003 RSI: ffff888039f56738 RDI: ffff888039f55b80
RBP: ffff888039f56738 R08: ffffffff8264ca1e R09: ffff888019c4f238
R10: dffffc0000000000 R11: ffffffff8264c980 R12: ffffffffffffff05
R13: ffff888039f56738 R14: ffff888039f55b80 R15: ffff888039f56738
FS: 00007f42cc300880(0000) GS:ffff88812643c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555587812a68 CR3: 0000000039d64000 CR4: 00000000003526f0
Call Trace:
mark_usage kernel/locking/lockdep.c:4654 [inline]
__lock_acquire+0x77c/0x2cf0 kernel/locking/lockdep.c:5191
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
down_read+0x97/0x200 kernel/locking/rwsem.c:1537
kernfs_dop_revalidate+0x9e/0x5e0 fs/kernfs/dir.c:1185
d_revalidate fs/namei.c:1030 [inline]
lookup_fast+0x253/0x5b0 fs/namei.c:-1
lookup_fast_for_open fs/namei.c:4520 [inline]
open_last_lookups fs/namei.c:4554 [inline]
path_openat+0x6a0/0x38a0 fs/namei.c:4827
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
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: 0033:0x7f42cc3ee407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffdde92b610 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f42cc300880 RCX: 00007f42cc3ee407
RDX: 0000000000080000 RSI: 00007ffdde92b790 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055c28a6337f5
R13: 000055c28a6337f5 R14: 0000000000000001 R15: 00007ffdde92fde0