======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.8.5443/25379 is trying to acquire lock:
ffff8880782f6460 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline]
ffff8880782f6460 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x69/0x80 fs/pipe.c:88

but task is already holding lock:
ffff888013982460 (sb_writers#6){.+.+}-{0:0}, at: __do_splice+0x33b/0x370 fs/splice.c:1431

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (sb_writers#6){.+.+}-{0:0}:
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       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_xattr_set+0x137/0x5a0 fs/overlayfs/xattrs.c:61
       ovl_own_xattr_set+0x86/0xd0 fs/overlayfs/xattrs.c:205
       __vfs_setxattr+0x175/0x1e0 fs/xattr.c:223
       __vfs_setxattr_noperm+0x127/0x660 fs/xattr.c:257
       __vfs_setxattr_locked+0x127/0x2b0 fs/xattr.c:318
       vfs_setxattr+0x14a/0x390 fs/xattr.c:344
       do_setxattr+0x145/0x180 fs/xattr.c:662
       filename_setxattr+0x167/0x1d0 fs/xattr.c:690
       path_setxattrat+0x1ff/0x3b0 fs/xattr.c:734
       __do_sys_setxattr fs/xattr.c:768 [inline]
       __se_sys_setxattr fs/xattr.c:764 [inline]
       __x64_sys_setxattr+0xc6/0x140 fs/xattr.c:764
       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 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
       inode_lock_shared include/linux/fs.h:1040 [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

-> #1 (&of->mutex){+.+.}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
       kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
       iter_file_splice_write+0x830/0x10b0 fs/splice.c:736
       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

-> #0 (&pipe->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:5253
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bc0 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
       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

other info that might help us debug this:

Chain exists of:
  &pipe->mutex --> &ovl_i_mutex_dir_key[depth] --> sb_writers#6

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_writers#6);
                               lock(&ovl_i_mutex_dir_key[depth]);
                               lock(sb_writers#6);
  lock(&pipe->mutex);

 *** DEADLOCK ***

locks held by syz.8.5443/25379: 1, last CPU#0:
 #0: ffff888013982460 (sb_writers#6){.+.+}-{0:0}, at: __do_splice+0x33b/0x370 fs/splice.c:1431

stack backtrace:
CPU: 0 UID: 0 PID: 25379 Comm: syz.8.5443 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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:5253
 lock_acquire kernel/locking/lockdep.c:5886 [inline]
 lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x1a4/0x1bc0 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
 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
RIP: 0033:0x7f217499e0d9
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:00007f2175852028 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007f2174c26090 RCX: 00007f217499e0d9
RDX: 000000000000000a RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007f2174a35024 R08: 00000000088000cc R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2174c26128 R14: 00007f2174c26090 R15: 00007fff2a295b48
 </TASK>