syzbot

INFO: task syz-executor:5956 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21592 pid:5956  tgid:5956  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 bit_wait+0x11/0xd0 kernel/sched/wait_bit.c:240
 __wait_on_bit+0xb9/0x310 kernel/sched/wait_bit.c:52
 out_of_line_wait_on_bit+0x123/0x170 kernel/sched/wait_bit.c:67
 wait_on_bit include/linux/wait_bit.h:77 [inline]
 gfs2_glock_wait+0xbd/0x2a0 fs/gfs2/glock.c:1268
 gfs2_glock_nq_init fs/gfs2/glock.h:252 [inline]
 __gfs2_lookup+0x117/0x270 fs/gfs2/inode.c:999
 __lookup_slow+0x297/0x3d0 fs/namei.c:1858
 lookup_slow+0x53/0x70 fs/namei.c:1875
 walk_component fs/namei.c:2221 [inline]
 lookup_last fs/namei.c:2722 [inline]
 path_lookupat+0x3f5/0x8c0 fs/namei.c:2746
 filename_lookup+0x212/0x570 fs/namei.c:2775
 user_path_at+0x3a/0x60 fs/namei.c:3567
 ksys_umount fs/namespace.c:2058 [inline]
 __do_sys_umount fs/namespace.c:2066 [inline]
 __se_sys_umount fs/namespace.c:2064 [inline]
 __x64_sys_umount+0xee/0x160 fs/namespace.c:2064
 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: 0033:0x7f9a50f90a77
RSP: 002b:00007ffc52af5328 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007f9a51013d7d RCX: 00007f9a50f90a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc52af53e0
RBP: 00007ffc52af53e0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc52af64d0
R13: 00007f9a51013d7d R14: 0000000000025d6b R15: 00007ffc52af8690
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/32:
 #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5586:
 #0: ffff88802fd2e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5956:
 #0: ffff888061e59528 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline]
 #0: ffff888061e59528 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1874
4 locks held by syz.1.164/6665:

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6622 Comm: kworker/0:6 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
RIP: 0010:lock_release+0x96/0x3b0 kernel/locking/lockdep.c:5888
Code: 02 00 00 65 4c 8b 3c 25 08 f0 7f 92 41 83 bf 2c 0b 00 00 00 0f 85 f7 01 00 00 49 81 3e c0 a3 43 93 0f 84 ea 01 00 00 9c 5b fa <48> c7 c7 5b 68 7a 8d e8 0e 8d bb 09 65 ff 05 27 16 e2 10 c7 44 24
RSP: 0018:ffffc9000b6bf9b0 EFLAGS: 00000087
RAX: 0000000000000000 RBX: 0000000000000287 RCX: 0000000080000002
RDX: 0000000000000000 RSI: ffffffff8bc083c0 RDI: ffffffff8bc08380
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520016d7f34 R12: ffff888075c4e4e0
R13: ffffffff86400074 R14: ffffffff8ea6cd78 R15: ffff888034228000
FS:  0000000000000000(0000) GS:ffff888125e21000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faf9cfff000 CR3: 000000007df3d000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
 _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 wg_ratelimiter_gc_entries+0x384/0x450 drivers/net/wireguard/ratelimiter.c:76
 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
 </TASK>