INFO: task udevd:5197 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:24184 pid:5197 tgid:5197 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5262 [inline]
__schedule+0x1836/0x4ed0 kernel/sched/core.c:6870
__schedule_loop kernel/sched/core.c:6952 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6967
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7024
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
bdev_open+0xe0/0xd30 block/bdev.c:962
blkdev_open+0x457/0x600 block/fops.c:702
do_dentry_open+0x7e4/0x1430 fs/open.c:962
vfs_open+0x3b/0x340 fs/open.c:1094
do_open fs/namei.c:4014 [inline]
path_openat+0x2efb/0x3860 fs/namei.c:4173
do_filp_open+0x1fa/0x410 fs/namei.c:4200
do_sys_openat2+0x121/0x1c0 fs/open.c:1434
do_sys_open fs/open.c:1449 [inline]
__do_sys_openat fs/open.c:1465 [inline]
__se_sys_openat fs/open.c:1460 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1460
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f690c8a7407
RSP: 002b:00007fff92c73b90 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f690cfaa880 RCX: 00007f690c8a7407
RDX: 00000000000a0800 RSI: 0000555f1e2eb660 RDI: ffffffffffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000555eef539100 R14: 0000000000000000 R15: 00007fff92c73e20
INFO: task syz.0.19:6042 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.19 state:D stack:27136 pid:6042 tgid:6041 ppid:5974 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5262 [inline]
__schedule+0x1836/0x4ed0 kernel/sched/core.c:6870
__schedule_loop kernel/sched/core.c:6952 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6967
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7024
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
bdev_release+0x1a9/0x650 block/bdev.c:1145
blkdev_release+0x15/0x20 block/fops.c:710
__fput+0x44c/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:233
get_signal+0x11ec/0x1340 kernel/signal.c:2807
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2e9/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3ad658f6c9
RSP: 002b:00007f3ad73a7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f3ad67e5fa0 RCX: 00007f3ad658f6c9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007f3ad6611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3ad67e6038 R14: 00007f3ad67e5fa0 R15: 00007ffd8fd53648
Showing all locks held in the system:
2 locks held by kworker/0:0/9:
#0: ffff8880b863a3d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
#1: ffff8880b8624248 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
1 lock held by khungtaskd/31:
#0: ffffffff8e33d560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e33d560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e33d560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/5197:
#0: ffff8881417c3358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962
2 locks held by getty/5589:
#0: ffff8880322c00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by kworker/0:2/5923:
#0: ffff8880b863a3d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
#1: ffff8880b8624248 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
1 lock held by udevd/5982:
#0: ffff8881417c3358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962
1 lock held by syz.0.19/6042:
#0: ffff8881417c3358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1a9/0x650 block/bdev.c:1145
3 locks held by syz.1.176/6423:
#0: ffff888141778a78 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x131/0xe10 drivers/block/nbd.c:1656
#1: ffff888141737668 (&q->q_usage_counter(io)#50){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#1: ffff888141737668 (&q->q_usage_counter(io)#50){++++}-{0:0}, at: nbd_add_socket+0x312/0xbb0 drivers/block/nbd.c:1262
#2: ffff8881417376a0 (&q->q_usage_counter(queue)#34){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline]
#2: ffff8881417376a0 (&q->q_usage_counter(queue)#34){+.+.}-{0:0}, at: nbd_add_socket+0x312/0xbb0 drivers/block/nbd.c:1262
1 lock held by syz.1.176/6424:
#0: ffff888141778a78 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x131/0xe10 drivers/block/nbd.c:1656
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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:336 [inline]
watchdog+0xfa8/0xff0 kernel/hung_task.c:499
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 83 f1 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 5e 24 00 f3 0f 1e fa fb f4 58 f1 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e007d80 EFLAGS: 000002c6
RAX: 2f86b8c59fbcb000 RBX: ffffffff8197bec7 RCX: 2f86b8c59fbcb000
RDX: 0000000000000001 RSI: ffffffff8da8b2a1 RDI: ffffffff8be14160
RBP: ffffffff8e007ea8 R08: ffff8880b863339b R09: 1ffff110170c6673
R10: dffffc0000000000 R11: ffffed10170c6674 R12: ffffffff8fbf6d70
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1c12a60
FS: 0000000000000000(0000) GS:ffff888125a78000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5f7a780f98 CR3: 00000000287bc000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e7/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3a7/0x410 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147