INFO: task syz.9.4403:22210 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.4403 state:D stack:25552 pid:22210 tgid:22209 ppid:21621 task_flags:0x40054c flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607
rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x41/0x60 fs/nfsd/nfsctl.c:1365
deactivate_locked_super+0xbc/0x130 fs/super.c:477
put_fs_context+0x93/0xb00 fs/fs_context.c:494
fscontext_release+0x65/0x80 fs/fsopen.c:79
__fput+0x42a/0xa80 fs/file_table.c:512
task_work_run+0x1d9/0x270 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x73a/0x2360 kernel/exit.c:1009
do_group_exit+0x22d/0x2f0 kernel/exit.c:1152
get_signal+0x121b/0x12c0 kernel/signal.c:3046
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb03f4be0d9
RSP: 002b:00007fb03d716028 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: 0000000000000000 RBX: 00007fb03f745fa0 RCX: 00007fb03f4be0d9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007fb03f555024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb03f746038 R14: 00007fb03f745fa0 R15: 00007ffda17525a8
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5337:
#0: ffff888036b3e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
3 locks held by syz.5.3677/18780:
3 locks held by kworker/1:4/19864:
3 locks held by syz.7.4278/21510:
#0: ffff8880394cfd28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88802b870500 (sb_writers#19){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
#1: ffff88802b870500 (sb_writers#19){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4e8ad8 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432
6 locks held by kworker/0:2/21832:
6 locks held by kworker/0:4/21833:
2 locks held by syz.9.4403/22210:
#0: ffff8880634280d0 (&type->s_umount_key#65){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880634280d0 (&type->s_umount_key#65){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880634280d0 (&type->s_umount_key#65){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:509
#1: ffffffff8e4e8ad8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
1 lock held by syz-executor/22358:
2 locks held by syz.6.4796/23764:
#0: ffffffff8f59d7e0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720 net/core/net_namespace.c:575
#1: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
3 locks held by syz.8.4831/23840:
1 lock held by syz.1.4835/23864:
=============================================
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 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
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+0xfd7/0x1030 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: 23864 Comm: syz.1.4835 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:preempt_count_add+0x13f/0x190 kernel/sched/core.c:5985
Code: 48 c7 c1 80 e5 a8 99 80 e1 07 80 c1 03 38 c1 0f 8c 01 ff ff ff 89 fb 48 c7 c7 80 e5 a8 99 e8 58 0a 9b 00 89 df e9 ec fe ff ff <48> c7 c1 80 e5 a8 99 80 e1 07 80 c1 03 38 c1 0f 8c 06 ff ff ff 89
RSP: 0018:ffffc90003fcf698 EFLAGS: 00000002
RAX: 0000000000000004 RBX: 0000000000000297 RCX: ffffffff99a8e503
RDX: 0000000000000000 RSI: ffffffff8bca5960 RDI: 0000000000000001
RBP: ffffffff89e81773 R08: ffffffff8faf4b37 R09: 1ffffffff1f5e966
R10: dffffc0000000000 R11: fffffbfff1f5e967 R12: 1ffff1100b658d5d
R13: dffffc0000000000 R14: ffff88805b2c6a98 R15: dffffc0000000000
FS: 00007f9d635256c0(0000) GS:ffff888125d46000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9d6533b7c0 CR3: 0000000050150000 CR4: 00000000003526f0
Call Trace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:131 [inline]
_raw_spin_lock_irqsave+0x24/0x60 kernel/locking/spinlock.c:166
rt_mutex_slowtrylock kernel/locking/rtmutex.c:1404 [inline]
rt_mutex_try_acquire kernel/locking/rtmutex.c:325 [inline]
__rt_mutex_lock kernel/locking/rtmutex.c:1839 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
mutex_lock_nested+0xe3/0x1d0 kernel/locking/rtmutex_api.c:578
__unix_dgram_recvmsg+0x1e3/0xd70 net/unix/af_unix.c:2580
sock_recvmsg_nosec+0x130/0x170 net/socket.c:1126
____sys_recvmsg+0x3ef/0x4b0 net/socket.c:2902
___sys_recvmsg+0x213/0x5a0 net/socket.c:2946
do_recvmmsg+0x320/0x7f0 net/socket.c:3041
__sys_recvmmsg net/socket.c:3115 [inline]
__do_sys_recvmmsg net/socket.c:3138 [inline]
__se_sys_recvmmsg net/socket.c:3131 [inline]
__x64_sys_recvmmsg+0x198/0x250 net/socket.c:3131
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: 0033:0x7f9d652ee0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9d63525028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f9d65576090 RCX: 00007f9d652ee0d9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f9d65385024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9d65576128 R14: 00007f9d65576090 R15: 00007fff68c94888