INFO: task syz.0.1268:10826 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1268 state:D stack:27656 pid:10826 tgid:10825 ppid:5812 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
sync_bdevs+0xfd/0x360 block/bdev.c:1288
ksys_sync+0xb2/0x150 fs/sync.c:105
__do_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f93b4f8eec9
RSP: 002b:00007f93b5df1038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f93b51e5fa0 RCX: 00007f93b4f8eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f93b51e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f93b51e6038 R14: 00007f93b51e5fa0 R15: 00007fff56526718
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e3c4460 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c4460 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c4460 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
1 lock held by klogd/5171:
#0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
#0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
2 locks held by getty/5569:
#0: ffff888031aab0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
6 locks held by kworker/0:4/5818:
#0: ffff8880236d9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc90003f7fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffff8880292a8198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff8880292a8198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1c0/0x4fe0 drivers/usb/core/hub.c:5898
#3: ffff888056bb5198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#3: ffff888056bb5198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
#4: ffff8880573a4160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff8880573a4160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4b0 drivers/base/dd.c:1006
#5: ffffffff8e2771d0 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xa9/0x250 kernel/umh.c:214
1 lock held by udevd/5829:
#0: ffff8880261e8358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945
4 locks held by kworker/u8:11/7414:
#0: ffff88801bad4948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc90004f3fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff900e5870 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669
#3: ffffffff8e3cf8c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3820
1 lock held by syz.0.1268/10826:
#0: ffff8880261e8358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0xfd/0x360 block/bdev.c:1288
5 locks held by kworker/u8:17/12208:
=============================================
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 10/02/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 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: 12208 Comm: kworker/u8:17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: 0x0 (events_unbound)
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:124 [inline]
RIP: 0010:lock_is_held_type+0x45/0x150 kernel/locking/lockdep.c:5933
Code: e3 1c 05 85 c9 0f 84 dd 00 00 00 65 8b 05 bb 5b 3e 08 85 c0 0f 85 ce 00 00 00 65 4c 8b 25 fb 19 3e 08 41 8b 94 24 2c 0b 00 00 <85> d2 0f 85 b6 00 00 00 48 89 fd 41 89 f6 9c 8f 04 24 fa 48 c7 c7
RSP: 0018:ffffc9000b697ba0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffffff90836954 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff88813fe40018
RBP: ffff88813ff7a800 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff88802da24900
R13: 00000000ffffffff R14: ffff888140404080 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881249d6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fedf53b12f8 CR3: 0000000079a46000 CR4: 00000000003526f0
Call Trace:
lock_is_held include/linux/lockdep.h:249 [inline]
pwq_dec_nr_active kernel/workqueue.c:1938 [inline]
pwq_dec_nr_in_flight+0x601/0xed0 kernel/workqueue.c:1997
process_one_work+0xe53/0x1b70 kernel/workqueue.c:3320
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245