======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-next-20250714-syzkaller #0 Not tainted
------------------------------------------------------
syz.6.574/8246 is trying to acquire lock:
ffff88807d480088 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154

but task is already holding lock:
ffff88805bfb0d58 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:182

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&p->lock){+.+.}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
       seq_read_iter+0xb7/0xe10 fs/seq_file.c:182
       copy_splice_read+0x54f/0x9b0 fs/splice.c:363
       do_splice_read fs/splice.c:979 [inline]
       splice_file_to_pipe+0x273/0x440 fs/splice.c:1289
       do_sendfile+0x475/0x7e0 fs/read_write.c:1376
       __do_sys_sendfile64 fs/read_write.c:1431 [inline]
       __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417
       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

-> #2 (&pipe->mutex){+.+.}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
       anon_pipe_write+0x16a/0x1360 fs/pipe.c:458
       __kernel_write_iter+0x3ec/0x860 fs/read_write.c:619
       __kernel_write+0xef/0x150 fs/read_write.c:639
       autofs_write fs/autofs/waitq.c:57 [inline]
       autofs_notify_daemon+0x748/0xe50 fs/autofs/waitq.c:164
       autofs_wait+0x11dc/0x1870 fs/autofs/waitq.c:426
       autofs_mount_wait+0x16b/0x330 fs/autofs/root.c:255
       autofs_d_automount+0x393/0x720 fs/autofs/root.c:401
       follow_automount fs/namei.c:1455 [inline]
       __traverse_mounts+0x308/0x5b0 fs/namei.c:1500
       traverse_mounts fs/namei.c:1529 [inline]
       handle_mounts fs/namei.c:1632 [inline]
       step_into+0x534/0xf30 fs/namei.c:1967
       open_last_lookups fs/namei.c:3834 [inline]
       path_openat+0x1bc6/0x3830 fs/namei.c:4043
       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

-> #1 (&sbi->pipe_mutex){+.+.}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
       autofs_write fs/autofs/waitq.c:55 [inline]
       autofs_notify_daemon+0x735/0xe50 fs/autofs/waitq.c:164
       autofs_wait+0x11dc/0x1870 fs/autofs/waitq.c:426
       autofs_mount_wait+0x16b/0x330 fs/autofs/root.c:255
       autofs_d_automount+0x393/0x720 fs/autofs/root.c:401
       follow_automount fs/namei.c:1455 [inline]
       __traverse_mounts+0x308/0x5b0 fs/namei.c:1500
       traverse_mounts fs/namei.c:1529 [inline]
       handle_mounts fs/namei.c:1632 [inline]
       step_into+0x534/0xf30 fs/namei.c:1967
       lookup_last fs/namei.c:2630 [inline]
       path_lookupat+0x163/0x430 fs/namei.c:2654
       filename_lookup+0x212/0x570 fs/namei.c:2683
       kern_path+0x35/0x50 fs/namei.c:2816
       lookup_bdev+0xc0/0x280 block/bdev.c:1205
       resume_store+0x169/0x460 kernel/power/hibernate.c:1295
       kernfs_fop_write_iter+0x375/0x4f0 fs/kernfs/file.c:334
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x548/0xa90 fs/read_write.c:686
       ksys_write+0x145/0x250 fs/read_write.c:738
       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

-> #0 (&of->mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
       kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154
       seq_read_iter+0x3f2/0xe10 fs/seq_file.c:225
       copy_splice_read+0x54f/0x9b0 fs/splice.c:363
       do_splice_read fs/splice.c:979 [inline]
       splice_file_to_pipe+0x273/0x440 fs/splice.c:1289
       do_sendfile+0x475/0x7e0 fs/read_write.c:1376
       __do_sys_sendfile64 fs/read_write.c:1431 [inline]
       __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417
       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

other info that might help us debug this:

Chain exists of:
  &of->mutex --> &pipe->mutex --> &p->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&p->lock);
                               lock(&pipe->mutex);
                               lock(&p->lock);
  lock(&of->mutex);

 *** DEADLOCK ***

2 locks held by syz.6.574/8246:
 #0: ffff888031b47468 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x2e/0x440 fs/splice.c:1286
 #1: ffff88805bfb0d58 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:182

stack backtrace:
CPU: 1 UID: 0 PID: 8246 Comm: syz.6.574 Not tainted 6.16.0-rc6-next-20250714-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 __mutex_lock_common kernel/locking/mutex.c:602 [inline]
 __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:747
 kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154
 seq_read_iter+0x3f2/0xe10 fs/seq_file.c:225
 copy_splice_read+0x54f/0x9b0 fs/splice.c:363
 do_splice_read fs/splice.c:979 [inline]
 splice_file_to_pipe+0x273/0x440 fs/splice.c:1289
 do_sendfile+0x475/0x7e0 fs/read_write.c:1376
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417
 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: 0033:0x7f533838e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f53391bd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f53385b6160 RCX: 00007f533838e929
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000000
RBP: 00007f5338410b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f53385b6160 R15: 00007fff873c7a48
 </TASK>