INFO: task syz.0.17:5851 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17 state:D stack:27232 pid:5851 tgid:5849 ppid:5774 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x169e/0x54f0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1662
__rt_mutex_slowlock kernel/locking/rtmutex.c:1739 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1779 [inline]
rt_mutex_slowlock+0x2dc/0x780 kernel/locking/rtmutex.c:1819
__rt_mutex_lock kernel/locking/rtmutex.c:1834 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:553
bdev_release+0x1af/0x660 block/bdev.c:1136
blkdev_release+0x15/0x20 block/fops.c:705
__fput+0x461/0xa70 fs/file_table.c:510
task_work_run+0x1d9/0x270 kernel/task_work.c:233
get_signal+0x11eb/0x1330 kernel/signal.c:2809
arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd02ed2cdd9
RSP: 002b:00007fd02e365028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007fd02efa6090 RCX: 00007fd02ed2cdd9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007fd02edc2d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd02efa6128 R14: 00007fd02efa6090 R15: 00007ffd9a5d8c08
Showing all locks held in the system:
1 lock held by khungtaskd/39:
#0: ffffffff8dfc8200 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8200 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8200 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777
2 locks held by getty/5368:
#0: ffff888036b830a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by udevd/5664:
#0: ffff8880269e74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by udevd/5791:
#0: ffff888026c274c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by syz.0.17/5851:
#0: ffff8880269e74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
1 lock held by udevd/5890:
#0: ffff888026a2f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by syz.1.20/5893:
#0: ffff888026a2f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
1 lock held by udevd/5939:
#0: ffff888026a474c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by syz.2.23/5943:
#0: ffff888026a474c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
1 lock held by udevd/5947:
#0: ffff888026a0f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by syz.3.26/5988:
#0: ffff888026a0f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
1 lock held by syz.4.27/6031:
#0: ffff888026c274c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
1 lock held by udevd/6040:
#0: ffff888026cf74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by udevd/6043:
#0: ffff888026ca74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by syz.5.28/6083:
#0: ffff888026ca74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
2 locks held by kworker/u8:2/6082:
#0: ffff888032a5a138 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284
#1: ffffc90004347c40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285
1 lock held by syz.6.29/6126:
#0: ffff888026cf74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
1 lock held by udevd/6127:
#0: ffff888026d5f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by udevd/6131:
#0: ffff888026e0f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:953
1 lock held by syz.7.30/6170:
#0: ffff888026d5f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
1 lock held by syz.8.31/6214:
#0: ffff888026e0f4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1af/0x660 block/bdev.c:1136
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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:162 [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:353 [inline]
watchdog+0xfd3/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 6082 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: bat_events batadv_dat_purge
RIP: 0010:check_preemption_disabled+0x6/0xe0 lib/smp_processor_id.c:14
Code: c7 c6 c0 68 a8 8b eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 <65> 8b 05 a7 bf 47 07 65 8b 0d 9c bf 47 07 f7 c1 ff ff ff 7f 74 0c
RSP: 0018:ffffc90004347958 EFLAGS: 00000046
RAX: 0000000080000000 RBX: ffffffff8b2b5e4a RCX: 0000000000000046
RDX: 0000000000000004 RSI: ffffffff8d687fd5 RDI: ffffffff8ba868e0
RBP: ffffc90004347ab8 R08: ffffffff8b2a2980 R09: ffffffff8dfc8200
R10: 0000000000000000 R11: fffffbfff1f152bf R12: dffffc0000000000
R13: 1ffff92000868f40 R14: ffff88805c59dd80 R15: ffff88805c59dd80
FS: 0000000000000000(0000) GS:ffff888125f25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f922c710560 CR3: 0000000040d56000 CR4: 00000000003526f0
Call Trace:
lockdep_hardirqs_off+0x8d/0xd0 kernel/locking/lockdep.c:4497
trace_hardirqs_off+0x12/0x40 kernel/trace/trace_preemptirq.c:104
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline]
_raw_spin_lock_irqsave+0x1a/0x60 kernel/locking/spinlock.c:166
rt_mutex_slowunlock+0xbf/0x8b0 kernel/locking/rtmutex.c:1426
spin_unlock_bh include/linux/spinlock_rt.h:115 [inline]
__batadv_dat_purge+0x335/0x400 net/batman-adv/distributed-arp-table.c:185
batadv_dat_purge+0x20/0x70 net/batman-adv/distributed-arp-table.c:204
process_one_work+0x9a3/0x1710 kernel/workqueue.c:3312
process_scheduled_works kernel/workqueue.c:3403 [inline]
worker_thread+0xba8/0x11e0 kernel/workqueue.c:3489
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245