INFO: task syz.0.3575:13432 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.3575 state:D stack:28104 pid:13432 tgid:13429 ppid:5850 task_flags:0x400040 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
device_lock include/linux/device.h:911 [inline]
usbdev_open+0x16e/0x790 drivers/usb/core/devio.c:1054
chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
do_dentry_open+0x9ae/0x1350 fs/open.c:965
vfs_open+0x3b/0x350 fs/open.c:1095
do_open fs/namei.c:3887 [inline]
path_openat+0x2ef1/0x3840 fs/namei.c:4046
do_filp_open+0x1fa/0x410 fs/namei.c:4073
do_sys_openat2+0x121/0x1c0 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1461
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f59697ad510
RSP: 002b:00007f5967a0db70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000028002 RCX: 00007f59697ad510
RDX: 0000000000028002 RSI: 00007f5967a0dc10 RDI: 00000000ffffff9c
RBP: 00007f5967a0dc10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007f59699f6038 R14: 00007f59699f5fa0 R15: 00007fff5802ec98
Showing all locks held in the system:
5 locks held by kworker/0:1/10:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/39:
#0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:7/1166:
5 locks held by kworker/u8:9/1420:
2 locks held by getty/5599:
#0: ffff88823bf740a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
5 locks held by kworker/0:3/5855:
1 lock held by syz.0.3575/13432:
#0: ffff888027d66188 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#0: ffff888027d66188 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x790 drivers/usb/core/devio.c:1054
1 lock held by syz-executor/13778:
1 lock held by syz.4.5100/16775:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 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]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5896 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5809 [inline]
RIP: 0010:preempt_count_add+0x9e/0x1a0 kernel/sched/core.c:5832
Code: 65 8b 05 65 72 66 10 25 ff ff ff 7f 39 f8 75 43 48 8b 5c 24 18 48 89 df e8 9f c4 0c 00 85 c0 74 09 31 db 31 ff e8 92 c4 0c 00 <65> 4c 8b 34 25 08 40 f6 91 49 81 c6 f0 14 00 00 4c 89 f0 48 c1 e8
RSP: 0018:ffffc90004fc7340 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff99018300
RDX: 0000000000000000 RSI: ffffffff8b621560 RDI: 0000000000000000
RBP: ffffc90004fc73f0 R08: ffffffff8f1d6037 R09: 1ffffffff1e3ac06
R10: dffffc0000000000 R11: fffffbfff1e3ac07 R12: dffffc0000000000
R13: ffff8880b893f870 R14: 0000000000000a06 R15: dffffc0000000000
FS: 00007fc73b169880(0000) GS:ffff8881269bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c278219 CR3: 0000000020b26000 CR4: 00000000003526f0
Call Trace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:109 [inline]
_raw_spin_lock_irqsave+0x8c/0xf0 kernel/locking/spinlock.c:162
rt_mutex_slowunlock+0xb0/0x8a0 kernel/locking/rtmutex.c:1417
spin_unlock include/linux/spinlock_rt.h:105 [inline]
___slab_alloc+0x4d2/0xdc0 mm/slub.c:3806
__slab_alloc mm/slub.c:3992 [inline]
__slab_alloc_node mm/slub.c:4067 [inline]
slab_alloc_node mm/slub.c:4228 [inline]
__do_kmalloc_node mm/slub.c:4375 [inline]
__kmalloc_node_track_caller_noprof+0x14c/0x450 mm/slub.c:4395
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:600
__alloc_skb+0x142/0x2d0 net/core/skbuff.c:669
alloc_skb include/linux/skbuff.h:1336 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
audit_buffer_alloc kernel/audit.c:1795 [inline]
audit_log_start+0x152/0x850 kernel/audit.c:1913
common_lsm_audit+0xba/0x2e0 security/lsm_audit.c:442
smack_log+0x394/0x3f0 security/smack/smack_access.c:391
smk_tskacc+0x2fc/0x370 security/smack/smack_access.c:255
smack_inode_permission+0x28f/0x320 security/smack/smack_lsm.c:1217
security_inode_permission+0xf8/0x310 security/security.c:2324
may_lookup fs/namei.c:1836 [inline]
link_path_walk+0x232/0xea0 fs/namei.c:2445
path_parentat fs/namei.c:2701 [inline]
__filename_parentat+0x246/0x670 fs/namei.c:2725
filename_parentat fs/namei.c:2743 [inline]
do_unlinkat+0xed/0x570 fs/namei.c:4625
__do_sys_unlink fs/namei.c:4696 [inline]
__se_sys_unlink fs/namei.c:4694 [inline]
__x64_sys_unlink+0x47/0x50 fs/namei.c:4694
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc73b2c5937
Code: 00 00 e9 a9 fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 5f 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 91 b4 0d 00 f7 d8 64 89 02 b8
RSP: 002b:00007ffde51c2f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc73b2c5937
RDX: 0000000000000000 RSI: 00000000000003dc RDI: 00007ffde51c2f80
RBP: 000055b821dc3f10 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffde51c2f80
R13: 000055b821da7520 R14: 000055b7e9a87100 R15: 000055b7e9a87140