INFO: task syz.0.42:5994 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.42 state:D stack:27880 pid:5994 ppid:5892 flags:0x00004006
Call Trace:
<TASK>
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
blkdev_put+0xff/0x760 block/bdev.c:944
blkdev_release+0x84/0x90 block/fops.c:604
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1d4/0x260 kernel/task_work.c:245
get_signal+0x1235/0x13f0 kernel/signal.c:2678
arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa21439c629
RSP: 002b:00007fa215171028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007fa214615fa0 RCX: 00007fa21439c629
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007fa214432b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa214616038 R14: 00007fa214615fa0 R15: 00007ffe2bd06708
</TASK>
Showing all locks held in the system:
3 locks held by kworker/u4:0/11:
1 lock held by khungtaskd/29:
#0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
1 lock held by syslogd/5118:
#0: ffff8880b8f3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
2 locks held by getty/5525:
#0: ffff88803207a0a0 (&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
1 lock held by udevd/5900:
#0: ffff8880222934c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by udevd/5901:
#0: ffff88802215b4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by udevd/5902:
#0: ffff8881407804c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by udevd/5903:
#0: ffff8880221c94c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by syz.0.42/5994:
#0: ffff8880221c94c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
1 lock held by syz.1.52/6028:
#0: ffff88802215b4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
1 lock held by syz.2.64/6073:
#0: ffff8881407804c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
1 lock held by syz.3.65/6088:
#0: ffff8880222934c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
1 lock held by udevd/6093:
#0: ffff8881407904c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by syz.4.70/6119:
#0: ffff8881407904c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
1 lock held by udevd/6149:
#0: ffff8880228034c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by syz.5.73/6151:
#0: ffff8880228034c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
1 lock held by udevd/6176:
#0: ffff8881407a04c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by syz.6.87/6201:
#0: ffff8881407a04c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
<TASK>
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
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:preempt_count_add+0x42/0x1a0 kernel/sched/core.c:5849
Code: 2c 97 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 eb 00 00 00 83 3d fe e6 cf 15 00 75 07 65 8b 05 3d 38 a7 7e 65 01 3d 36 38 a7 7e <48> c7 c0 80 64 2c 97 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 e6 00
RSP: 0018:ffffc900001174b8 EFLAGS: 00000282
RAX: 0000000080000001 RBX: 1ffff92000022eb5 RCX: ffffffff972c6403
RDX: ffff88801a27da00 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffc90000117670 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc900001175a8
R13: dffffc0000000000 R14: ffffc900001175e0 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0084bc000 CR3: 000000000cf32000 CR4: 00000000003506e0
Call Trace:
<TASK>
unwind_next_frame+0xbe/0x2970 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
__kmem_cache_free+0xba/0x1e0 mm/slub.c:3843
skb_kfree_head net/core/skbuff.c:949 [inline]
skb_free_head net/core/skbuff.c:961 [inline]
skb_release_data+0x634/0x800 net/core/skbuff.c:991
skb_release_all net/core/skbuff.c:1057 [inline]
__kfree_skb net/core/skbuff.c:1071 [inline]
consume_skb+0xb2/0x110 net/core/skbuff.c:1287
nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline]
nsim_dev_trap_report_work+0x76f/0xb00 drivers/net/netdevsim/dev.c:851
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
</TASK>