INFO: task syz.1.7259:26151 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.7259 state:D stack:27896 pid:26151 tgid:26150 ppid:24049 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x16ec/0x5620 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2cc/0x5e0 kernel/sched/completion.c:153
__flush_work+0x9e0/0xda0 kernel/workqueue.c:4366
p9_mux_poll_stop net/9p/trans_fd.c:140 [inline]
p9_conn_destroy net/9p/trans_fd.c:804 [inline]
p9_fd_close+0x226/0x400 net/9p/trans_fd.c:840
p9_client_create+0x6b4/0xcc0 net/9p/client.c:937
v9fs_session_init+0x46/0xe60 fs/9p/v9fs.c:446
v9fs_get_tree+0xbd/0xac0 fs/9p/vfs_super.c:97
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3758 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3834
do_mount fs/namespace.c:4167 [inline]
__do_sys_mount fs/namespace.c:4383 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4360
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe637d1ce59
RSP: 002b:00007fe635f6e028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe637f95fa0 RCX: 00007fe637d1ce59
RDX: 0000200000000080 RSI: 0000200000000300 RDI: 0000000000000000
RBP: 00007fe637db2d6f R08: 0000200000000180 R09: 0000000000000000
R10: 0000000000804000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe637f96038 R14: 00007fe637f95fa0 R15: 00007ffda75258e8
Showing all locks held in the system:
5 locks held by ktimers/1/29:
3 locks held by kworker/1:1/36:
1 lock held by khungtaskd/38:
#0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:2/42:
2 locks held by getty/5364:
#0: ffff8880297ed0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cc32e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by udevd/19341:
#0: ffff888037dbc480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
1 lock held by syz-executor/23297:
#0: ffff88802804e480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
2 locks held by kworker/0:3/23659:
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
#0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
#1: ffffc90006d77c40 (p9_poll_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
#1: ffffc90006d77c40 (p9_poll_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
4 locks held by kworker/u8:0/24104:
2 locks held by kworker/0:4/24373:
4 locks held by kworker/u8:1/24471:
5 locks held by syz.7.7792/27800:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 29 Comm: ktimers/1 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline]
RIP: 0010:do_raw_spin_unlock+0x61/0x210 kernel/locking/spinlock_debug.c:141
Code: 4e ad de 0f 85 c6 00 00 00 48 89 df be 04 00 00 00 e8 73 a8 8a 00 48 89 d8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 47 01 00 00 <83> 3b 00 0f 84 bd 00 00 00 4c 8d 73 10 4d 89 f5 49 c1 ed 03 43 80
RSP: 0000:ffffc90000a3fb30 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88804203a1d8 RCX: ffffffff81a0f2ad
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88804203a1d8
RBP: ffffc90000a3fc80 R08: ffff88804203a1db R09: 1ffff1100840743b
R10: dffffc0000000000 R11: ffffed100840743c R12: dffffc0000000000
R13: 1ffff92000147f78 R14: ffff88804203a1dc R15: ffff88804203a1d8
FS: 0000000000000000(0000) GS:ffff888126287000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30004ff8 CR3: 0000000035ab2000 CR4: 00000000003526f0
Call Trace:
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:177 [inline]
_raw_spin_unlock_irqrestore+0x23/0x80 kernel/locking/spinlock.c:198
unlock_rt_mutex_safe kernel/locking/rtmutex.c:350 [inline]
rt_mutex_slowunlock+0x4a7/0x8b0 kernel/locking/rtmutex.c:1463
spin_unlock include/linux/spinlock_rt.h:109 [inline]
net_tx_action+0x9dd/0xc30 net/core/dev.c:5855
handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
run_ktimerd+0x69/0x100 kernel/softirq.c:1151
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
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