INFO: task syz.1.4338:21565 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.4338 state:D stack:26696 pid:21565 ppid:13113 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
sync_bdevs+0x1af/0x330 block/bdev.c:1076
ksys_sync+0xc6/0x170 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fae1979aeb9
RSP: 002b:00007fae1a72b028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fae19a15fa0 RCX: 00007fae1979aeb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fae19a15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fae19a16038 R14: 00007fae19a15fa0 R15: 00007ffdaca91498
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by getty/5529:
#0: ffff88814cc0d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217
2 locks held by kworker/u4:10/16711:
1 lock held by udevd/21284:
#0: ffff888141b634c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by syz.1.4338/21565:
#0: ffff888141b634c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf3d/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 19843 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:check_preemption_disabled+0x3/0x110 lib/smp_processor_id.c:13
Code: ff ff ff cc cc cc cc f3 0f 1e fa 48 c7 c7 80 80 1c 8b 48 c7 c6 c0 80 1c 8b eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 41 57 <41> 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65
RSP: 0018:ffffc90003567a08 EFLAGS: 00000283
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81682307
RDX: 0000000000000000 RSI: ffffffff8b1c80c0 RDI: ffffffff8b1c8080
RBP: ffffc90003567b48 R08: ffffffff8e8ad9ef R09: 1ffffffff1d15b3d
R10: dffffc0000000000 R11: fffffbfff1d15b3e R12: 1ffff920006acf54
R13: ffffffff8d131fe0 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a5b8dfe168 CR3: 000000000cf32000 CR4: 00000000003506f0
Call Trace:
rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0xc6/0x420 kernel/locking/lockdep.c:5725
rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
rcu_read_lock include/linux/rcupdate.h:786 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
batadv_nc_worker+0xef/0x610 net/batman-adv/network-coding.c:719
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293