====================================================== WARNING: possible circular locking dependency detected 6.15.0-rc3-syzkaller-00032-ga79be02bba5c #0 Not tainted ------------------------------------------------------ syz.1.2458/25186 is trying to acquire lock: ffff88805aad4068 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x322/0x1530 fs/splice.c:683 but task is already holding lock: ffff88805b11c420 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xd1f/0x1920 fs/splice.c:1347 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (sb_writers#5){.+.+}-{0:0}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 percpu_down_read include/linux/percpu-rwsem.h:52 [inline] __sb_start_write include/linux/fs.h:1783 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1919 mnt_want_write+0x3f/0x90 fs/namespace.c:556 ovl_create_object+0x13c/0x3b0 fs/overlayfs/dir.c:628 lookup_open fs/namei.c:3701 [inline] open_last_lookups fs/namei.c:3800 [inline] path_openat+0x194b/0x35d0 fs/namei.c:4036 do_filp_open+0x284/0x4e0 fs/namei.c:4066 do_sys_openat2+0x12b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x249/0x2a0 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 down_read+0xb3/0xa50 kernel/locking/rwsem.c:1524 inode_lock_shared include/linux/fs.h:877 [inline] lookup_slow+0x45/0x70 fs/namei.c:1833 walk_component+0x2f4/0x420 fs/namei.c:2138 lookup_last fs/namei.c:2636 [inline] path_lookupat+0x169/0x440 fs/namei.c:2660 filename_lookup+0x290/0x670 fs/namei.c:2689 kern_path+0x35/0x50 fs/namei.c:2822 lookup_bdev+0xc8/0x290 block/bdev.c:1167 resume_store+0x1e1/0x720 kernel/power/hibernate.c:1248 kernfs_fop_write_iter+0x398/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x70f/0xd10 fs/read_write.c:684 ksys_write+0x19d/0x2d0 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&of->mutex){+.+.}-{4:4}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746 kernfs_seq_start+0x53/0x3b0 fs/kernfs/file.c:154 traverse+0x14f/0x550 fs/seq_file.c:106 seq_read_iter+0xc7f/0xda0 fs/seq_file.c:195 do_iter_readv_writev+0x71f/0x9d0 fs/read_write.c:-1 vfs_readv+0x2b5/0xa80 fs/read_write.c:1016 do_preadv fs/read_write.c:1130 [inline] __do_sys_preadv fs/read_write.c:1177 [inline] __se_sys_preadv fs/read_write.c:1172 [inline] __x64_sys_preadv+0x1ba/0x2d0 fs/read_write.c:1172 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&p->lock){+.+.}-{4:4}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746 seq_read_iter+0xb4/0xda0 fs/seq_file.c:182 copy_splice_read+0x63f/0xb50 fs/splice.c:363 do_splice_read fs/splice.c:979 [inline] splice_file_to_pipe+0x290/0x500 fs/splice.c:1289 do_sendfile+0x526/0x8c0 fs/read_write.c:1374 __do_sys_sendfile64 fs/read_write.c:1423 [inline] __se_sys_sendfile64+0x102/0x1e0 fs/read_write.c:1415 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&pipe->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746 iter_file_splice_write+0x322/0x1530 fs/splice.c:683 do_splice_from fs/splice.c:935 [inline] do_splice+0xda7/0x1920 fs/splice.c:1348 __do_splice fs/splice.c:1430 [inline] __do_sys_splice fs/splice.c:1633 [inline] __se_sys_splice+0x2dc/0x450 fs/splice.c:1615 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 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: &pipe->mutex --> &ovl_i_mutex_dir_key[depth] --> sb_writers#5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#5); lock(&ovl_i_mutex_dir_key[depth]); lock(sb_writers#5); lock(&pipe->mutex); *** DEADLOCK *** 1 lock held by syz.1.2458/25186: #0: ffff88805b11c420 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xd1f/0x1920 fs/splice.c:1347 stack backtrace: CPU: 0 UID: 0 PID: 25186 Comm: syz.1.2458 Not tainted 6.15.0-rc3-syzkaller-00032-ga79be02bba5c #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211 check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746 iter_file_splice_write+0x322/0x1530 fs/splice.c:683 do_splice_from fs/splice.c:935 [inline] do_splice+0xda7/0x1920 fs/splice.c:1348 __do_splice fs/splice.c:1430 [inline] __do_sys_splice fs/splice.c:1633 [inline] __se_sys_splice+0x2dc/0x450 fs/splice.c:1615 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fedae18e969 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:00007fedaf0bf038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007fedae3b5fa0 RCX: 00007fedae18e969 RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007fedae210ab1 R08: 0000000800000008 R09: 0000000000000008 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fedae3b5fa0 R15: 00007ffc61864948