INFO: task udevd:7362 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:22928 pid:7362 ppid:3640 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x562/0xaf0 kernel/locking/mutex.c:747
device_lock include/linux/device.h:885 [inline]
uevent_show+0x16c/0x320 drivers/base/core.c:2669
dev_attr_show+0x50/0xb0 drivers/base/core.c:2372
sysfs_kf_seq_show+0x349/0x4b0 fs/sysfs/file.c:59
seq_read_iter+0x49b/0xd50 fs/seq_file.c:230
call_read_iter include/linux/fs.h:2259 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x4a7/0xa00 fs/read_write.c:470
ksys_read+0x14c/0x250 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8e8faa7407
RSP: 002b:00007fffdf11fef0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f8e90290880 RCX: 00007f8e8faa7407
RDX: 0000000000001000 RSI: 000055d98cc06150 RDI: 0000000000000008
RBP: 00007f8e8fbefff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f8e8fbefea0 R14: 0000000000000000 R15: 000055d98cbfb7d0
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e7f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2f010 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2de60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2de60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2de60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by pvrusb2-context/2312:
#0: ffff888074f48188 (&hdw->big_lock_mutex){+.+.}-{3:3}, at: pvr2_hdw_initialize+0xe1/0x3c10 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2326
#1: ffffffff8c9da930 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0xf9/0x2b0 kernel/umh.c:218
2 locks held by getty/4029:
#0: ffff88814d33a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198
6 locks held by kworker/1:6/4338:
#0: ffff8881446e5138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#1: ffffc90004397d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#2: ffff888145f62190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888145f62190 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x5560 drivers/usb/core/hub.c:5845
#3: ffff888056cab190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff888056cab190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x107/0x8a0 drivers/usb/core/hub.c:2305
#4: ffff8880305d2118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#4: ffff8880305d2118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1100 [inline]
#4: ffff8880305d2118 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb2/0x850 drivers/base/dd.c:1303
#5: ffff888074f48188 (&hdw->big_lock_mutex){+.+.}-{3:3}, at: pvr2_hdw_disconnect+0x69/0x500 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2710
4 locks held by udevd/7362:
#0: ffff888057c732f0 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
#1: ffff88801fbef488 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x58/0x410 fs/kernfs/file.c:172
#2: ffff88814826a918 (kn->active#5){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff88814826a918 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
#3: ffff888056cab190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff888056cab190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2669
4 locks held by udevd/13058:
#0: ffff888057980668 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
#1: ffff888055c92c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x58/0x410 fs/kernfs/file.c:172
#2: ffff888145b0eae8 (kn->active#5){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888145b0eae8 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
#3: ffff888145f8a190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#3: ffff888145f8a190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2669
3 locks held by kworker/0:13/13198:
#0: ffff8881446e5138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#1: ffffc900034ffd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
#2: ffff888145f8a190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
#2: ffff888145f8a190 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x5560 drivers/usb/core/hub.c:5845
1 lock held by syz.6.2614/14561:
#0: ffffffff8cb33a00 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023
2 locks held by rm/14581:
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8592 Comm: kworker/u4:10 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:717 [inline]
RIP: 0010:rcu_is_watching+0x2/0xa0 kernel/rcu/tree.c:720
Code: 8a e8 52 e3 c2 08 48 c7 c7 60 49 b3 8c 4c 89 f6 e8 43 ca cc 02 e9 44 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 57 <41> 56 53 65 ff 05 1c fc 95 7e e8 cf f7 c2 08 89 c3 83 f8 08 73 60
RSP: 0018:ffffc9000d537bd0 EFLAGS: 00000202
RAX: ffffffff89f8792f RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888024a80000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88807c8d5e10 R08: dffffc0000000000 R09: 1ffffffff215fe48
R10: dffffc0000000000 R11: fffffbfff215fe49 R12: dffffc0000000000
R13: ffffffff89f878fe R14: ffff8880558c8c80 R15: 00000000000003c2
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dd1b065138 CR3: 0000000074f99000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_read_lock include/linux/rcupdate.h:792 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
batadv_nc_worker+0x108/0x600 net/batman-adv/network-coding.c:719
process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295