======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor311/5632 is trying to acquire lock:
ffff88807b1d2480 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165

but task is already holding lock:
ffff8880369babd8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&p->lock){+.+.}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
       seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
       kernfs_fop_read_iter+0x46c/0x610 fs/kernfs/file.c:290
       copy_splice_read+0x4ba/0xbb0 fs/splice.c:362
       do_splice_read fs/splice.c:980 [inline]
       do_splice_read+0x285/0x370 fs/splice.c:954
       splice_file_to_pipe+0x82/0x120 fs/splice.c:1290
       do_sendfile+0x366/0xe20 fs/read_write.c:1377
       __do_sys_sendfile64 fs/read_write.c:1432 [inline]
       __se_sys_sendfile64 fs/read_write.c:1418 [inline]
       __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1418
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&pipe->mutex){+.+.}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
       pipe_lock fs/pipe.c:91 [inline]
       pipe_lock+0x69/0x80 fs/pipe.c:88
       iter_file_splice_write+0x1fd/0x10b0 fs/splice.c:682
       backing_file_splice_write+0x27b/0x820 fs/backing-file.c:318
       ovl_splice_write+0x328/0x610 fs/overlayfs/file.c:433
       do_splice_from fs/splice.c:936 [inline]
       do_splice+0x109c/0x1fa0 fs/splice.c:1349
       __do_splice+0x33b/0x370 fs/splice.c:1431
       __do_sys_splice fs/splice.c:1634 [inline]
       __se_sys_splice fs/splice.c:1616 [inline]
       __x64_sys_splice+0x187/0x250 fs/splice.c:1616
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (sb_writers#4){.+.+}-{0:0}:
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
       percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
       __sb_start_write include/linux/fs/super.h:19 [inline]
       sb_start_write include/linux/fs/super.h:125 [inline]
       mnt_want_write+0x6f/0x420 fs/namespace.c:494
       ovl_create_object+0x130/0x3b0 fs/overlayfs/dir.c:705
       lookup_open+0x1255/0x1990 fs/namei.c:4567
       open_last_lookups fs/namei.c:4767 [inline]
       path_openat+0xa2c/0x2440 fs/namei.c:4997
       do_file_open+0x20e/0x430 fs/namei.c:5029
       do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
       do_sys_open fs/open.c:1423 [inline]
       __do_sys_open fs/open.c:1431 [inline]
       __se_sys_open fs/open.c:1427 [inline]
       __x64_sys_open+0xfe/0x1d0 fs/open.c:1427
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
       inode_lock_shared include/linux/fs.h:1039 [inline]
       lookup_slow+0x42/0x70 fs/namei.c:1935
       walk_component fs/namei.c:2282 [inline]
       lookup_last fs/namei.c:2789 [inline]
       path_lookupat+0x5e8/0xc40 fs/namei.c:2813
       filename_lookup+0x202/0x590 fs/namei.c:2842
       kern_path+0x37/0x50 fs/namei.c:3036
       lookup_bdev+0xd8/0x2a0 block/bdev.c:1268
       resume_store+0x1d6/0x460 kernel/power/hibernate.c:1278
       kobj_attr_store+0x58/0x80 lib/kobject.c:842
       sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
       kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x6af/0x1050 fs/read_write.c:687
       ksys_write+0x12a/0x250 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&of->mutex){+.+.}-{4:4}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
       check_prevs_add kernel/locking/lockdep.c:3300 [inline]
       validate_chain kernel/locking/lockdep.c:3924 [inline]
       __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
       kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
       seq_read_iter+0x2c1/0x1270 fs/seq_file.c:226
       kernfs_fop_read_iter+0x46c/0x610 fs/kernfs/file.c:290
       copy_splice_read+0x4ba/0xbb0 fs/splice.c:362
       do_splice_read fs/splice.c:980 [inline]
       do_splice_read+0x285/0x370 fs/splice.c:954
       splice_file_to_pipe+0x82/0x120 fs/splice.c:1290
       do_sendfile+0x366/0xe20 fs/read_write.c:1377
       __do_sys_sendfile64 fs/read_write.c:1432 [inline]
       __se_sys_sendfile64 fs/read_write.c:1418 [inline]
       __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1418
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       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 ***

locks held by syz-executor311/5632: 2, last CPU#0:
 #0: ffff88807b064c60 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline]
 #0: ffff88807b064c60 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x69/0x80 fs/pipe.c:88
 #1: ffff8880369babd8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183

stack backtrace:
CPU: 0 UID: 0 PID: 5632 Comm: syz-executor311 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
 check_prevs_add kernel/locking/lockdep.c:3300 [inline]
 validate_chain kernel/locking/lockdep.c:3924 [inline]
 __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
 lock_acquire kernel/locking/lockdep.c:5908 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
 kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
 seq_read_iter+0x2c1/0x1270 fs/seq_file.c:226
 kernfs_fop_read_iter+0x46c/0x610 fs/kernfs/file.c:290
 copy_splice_read+0x4ba/0xbb0 fs/splice.c:362
 do_splice_read fs/splice.c:980 [inline]
 do_splice_read+0x285/0x370 fs/splice.c:954
 splice_file_to_pipe+0x82/0x120 fs/splice.c:1290
 do_sendfile+0x366/0xe20 fs/read_write.c:1377
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64 fs/read_write.c:1418 [inline]
 __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1418
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1d6e0454a9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1d6dfdb1d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f1d6e0f5b88 RCX: 00007f1d6e0454a9
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000006
RBP: 00007f1d6e0f5b80 R08: 00007f1d6dfdb6c0 R09: 35203a6b63617473
R10: 0000000000000004 R11: 0000000000000246 R12: 00007f1d6e0c7380
R13: 0000200000000040 R14: 00002000000002c0 R15: 00007f1d6e0c105f
 </TASK>