INFO: task syz.0.56:4706 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.56 state:D stack:25216 pid:4706 ppid:4264 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:815
blkdev_open+0x11e/0x2e0 block/fops.c:500
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3626 [inline]
path_openat+0x25c6/0x2e70 fs/namei.c:3783
do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
do_sys_openat2+0x142/0x490 fs/open.c:1318
do_sys_open fs/open.c:1334 [inline]
__do_sys_openat fs/open.c:1350 [inline]
__se_sys_openat fs/open.c:1345 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1345
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa9c038d510
RSP: 002b:00007fa9be5f5b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000149440 RCX: 00007fa9c038d510
RDX: 0000000000149440 RSI: 00007fa9be5f5c10 RDI: 00000000ffffff9c
RBP: 00007fa9be5f5c10 R08: 0000000000000000 R09: 002364626e2f7665
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007fa9c05d6038 R14: 00007fa9c05d5fa0 R15: 00007fff3a77ab98
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2b570 (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: ffffffff8cb2bd90 (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: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4024:
#0: ffff88807f4f0098 (&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+0x41b/0x1380 drivers/tty/n_tty.c:2198
5 locks held by kworker/0:7/4330:
#0: ffff88801c2f9d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1:
ffffc9000484fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff88823bc6c990 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
#2: ffff88823bc6c990 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x54e0 drivers/usb/core/hub.c:5845
#3: ffff8880568a0190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
#3: ffff8880568a0190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990
#4: ffff88802a44d118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
#4: ffff88802a44d118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990
1 lock held by udevd/4392:
#0: ffff888024f6a4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:815
6 locks held by kworker/0:10/4487:
#0: ffff88801c2f9d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90004cbfd00 ((work_completion)(&hub->events)){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff888144f88190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
#2: ffff888144f88190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x54e0 drivers/usb/core/hub.c:5845
#3: ffff88805bbb2190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
#3: ffff88805bbb2190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990
#4: ffff88805b448118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
#4: ffff88805b448118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:990
#5: ffffffff8c9d7790 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0xec/0x2a0 kernel/umh.c:218
1 lock held by syz.0.56/4706:
#0: ffff888024f6a4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:815
3 locks held by kworker/u4:26/5379:
#0: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545
#1: ffff8880b8f27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999
#2: ffff8880b8f28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
=============================================
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 07/12/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 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: 29 Comm: kworker/u4:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
RIP: 0010:rcu_read_lock include/linux/rcupdate.h:791 [inline]
RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
RIP: 0010:batadv_nc_worker+0xd5/0x600 net/batman-adv/network-coding.c:719
Code: 20 00 74 08 48 89 df e8 69 a1 ef f7 4a 8d 2c fd 00 00 00 00 48 03 2b e8 09 86 8a f7 4c 8d 2d 00 00 00 00 48 c7 c7 e0 ab b2 8c <31> f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 41 55 e8 c5 a0 81 f7
RSP: 0018:ffffc90000a5fbe0 EFLAGS: 00000283
RAX: 0000000000000001 RBX: ffff88807db333c0 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff8a8c1680 RDI: ffffffff8cb2abe0
RBP: ffff88802fcac450 R08: dffffc0000000000 R09: fffffbfff1c3eea6
R10: fffffbfff1c3eea6 R11: 1ffffffff1c3eea5 R12: dffffc0000000000
R13: ffffffff89e1507e R14: ffff8880568f8c80 R15: 000000000000008a
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f710ff8 CR3: 000000000c88e000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295