INFO: task syz.4.347:8194 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.347 state:D stack:23960 pid:8194 tgid:8193 ppid:5799 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x145f/0x5070 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760
__rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114
rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline]
__down_read kernel/locking/rwsem.c:1466 [inline]
down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539
__super_lock fs/super.c:59 [inline]
super_lock+0x2a9/0x3b0 fs/super.c:121
__iterate_supers+0x126/0x290 fs/super.c:923
ksys_sync+0x94/0x150 fs/sync.c:102
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fca6193f749
RSP: 002b:00007fca5fba6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fca61b95fa0 RCX: 00007fca6193f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fca61b95fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fca61b96038 R14: 00007fca61b95fa0 R15: 00007ffe6ab656a8
Showing all locks held in the system:
3 locks held by kworker/1:0/31:
#0: ffff88813ff55138 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813ff55138 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
#1: ffffc90000a5fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90000a5fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
#2: ffff888030008260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x224/0x3e0 drivers/net/netdevsim/fib.c:1490
1 lock held by khungtaskd/38:
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by udevd/5166:
2 locks held by getty/5554:
#0: ffff88814e7c50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x44f/0x1460 drivers/tty/n_tty.c:2211
3 locks held by syz-executor/5797:
4 locks held by syz-executor/5798:
2 locks held by syz-executor/6175:
1 lock held by syz.4.347/8194:
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by udevd/8281:
2 locks held by udevd/8325:
1 lock held by syz.8.362/8403:
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by syz.8.362/8405:
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by udevd/8945:
3 locks held by udevd/8948:
5 locks held by kworker/u8:30/8976:
1 lock held by syz.3.451/9124:
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff888063f580d0 (&type->s_umount_key#64){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
2 locks held by syz.9.510/9449:
2 locks held by syz.6.511/9468:
2 locks held by syz.7.513/9474:
1 lock held by rm/9475:
3 locks held by syz.2.514/9477:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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:160 [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:346 [inline]
watchdog+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 3529 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: kvfree_rcu_reclaim kfree_rcu_work
RIP: 0010:trace_hardirqs_off+0x2f/0x40 kernel/trace/trace_preemptirq.c:109
Code: 48 8b 5c 24 08 48 89 df e8 fe 1c 0a 09 65 8b 05 1f b1 ec 0f 85 c0 74 07 5b c3 cc cc cc cc cc 65 c7 05 09 b1 ec 0f 01 00 00 00 <48> 89 df 5b e9 b8 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffc9000e9af940 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffffff8ad5124a RCX: 0000000000000046
RDX: 0000000000000006 RSI: ffffffff8ce0bbc5 RDI: ffffffff8b3f57e0
RBP: 0000000000000000 R08: ffffffff8edb3477 R09: 1ffffffff1db668e
R10: dffffc0000000000 R11: fffffbfff1db668f R12: 0000000000000115
R13: ffffffff98ebd3d8 R14: ffffffff98ebd3e0 R15: ffff888032b2ef80
FS: 0000000000000000(0000) GS:ffff888126cef000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f82ece46000 CR3: 000000003668a000 CR4: 00000000003526f0
Call Trace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
_raw_spin_lock_irqsave+0x1a/0x60 kernel/locking/spinlock.c:162
debug_object_deactivate+0x6d/0x360 lib/debugobjects.c:873
debug_rcu_head_unqueue kernel/rcu/rcu.h:248 [inline]
debug_rcu_bhead_unqueue mm/slab_common.c:1439 [inline]
kvfree_rcu_bulk+0x5a/0x1f0 mm/slab_common.c:1516
kfree_rcu_work+0xed/0x170 mm/slab_common.c:1601
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246