====================================================== WARNING: possible circular locking dependency detected 6.15.0-next-20250530-syzkaller #0 Not tainted ------------------------------------------------------ syz.6.952/10294 is trying to acquire lock: ffff88805b95ec68 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x1e6/0x1000 fs/splice.c:683 but task is already holding lock: ffff88801b694428 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xbff/0x1660 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+0x120/0x360 kernel/locking/lockdep.c:5871 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.h:1793 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1929 mnt_want_write+0x41/0x90 fs/namespace.c:557 ovl_create_object+0xfc/0x310 fs/overlayfs/dir.c:628 lookup_open fs/namei.c:3708 [inline] open_last_lookups fs/namei.c:3807 [inline] path_openat+0x14f1/0x3830 fs/namei.c:4043 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 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 -> #3 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1524 inode_lock_shared include/linux/fs.h:882 [inline] lookup_slow+0x46/0x70 fs/namei.c:1833 walk_component+0x2d2/0x400 fs/namei.c:2138 lookup_last fs/namei.c:2639 [inline] path_lookupat+0x163/0x430 fs/namei.c:2663 filename_lookup+0x212/0x570 fs/namei.c:2692 kern_path+0x35/0x50 fs/namei.c:2825 lookup_bdev+0xc0/0x280 block/bdev.c:1205 resume_store+0x169/0x460 kernel/power/hibernate.c:1272 kernfs_fop_write_iter+0x378/0x4f0 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x54b/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 -> #2 (&of->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 kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:154 seq_read_iter+0x3ef/0xe10 fs/seq_file.c:225 copy_splice_read+0x552/0x9b0 fs/splice.c:363 do_splice_read fs/splice.c:979 [inline] splice_direct_to_actor+0x4a9/0xcc0 fs/splice.c:1083 do_splice_direct_actor fs/splice.c:1201 [inline] do_splice_direct+0x181/0x270 fs/splice.c:1227 do_sendfile+0x4da/0x7e0 fs/read_write.c:1370 __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 -> #1 (&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+0x552/0x9b0 fs/splice.c:363 do_splice_read fs/splice.c:979 [inline] splice_file_to_pipe+0x270/0x440 fs/splice.c:1289 do_splice+0xdc0/0x1660 fs/splice.c:1373 __do_splice fs/splice.c:1430 [inline] __do_sys_splice fs/splice.c:1633 [inline] __se_sys_splice+0x2e1/0x460 fs/splice.c:1615 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 (&pipe->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 iter_file_splice_write+0x1e6/0x1000 fs/splice.c:683 do_splice_from fs/splice.c:935 [inline] do_splice+0xc76/0x1660 fs/splice.c:1348 __do_splice fs/splice.c:1430 [inline] __do_sys_splice fs/splice.c:1633 [inline] __se_sys_splice+0x2e1/0x460 fs/splice.c:1615 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: &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.6.952/10294: #0: ffff88801b694428 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xbff/0x1660 fs/splice.c:1347 stack backtrace: CPU: 1 UID: 0 PID: 10294 Comm: syz.6.952 Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: 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 iter_file_splice_write+0x1e6/0x1000 fs/splice.c:683 do_splice_from fs/splice.c:935 [inline] do_splice+0xc76/0x1660 fs/splice.c:1348 __do_splice fs/splice.c:1430 [inline] __do_sys_splice fs/splice.c:1633 [inline] __se_sys_splice+0x2e1/0x460 fs/splice.c:1615 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: 0033:0x7eff6758e969 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:00007eff6840d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007eff677b5fa0 RCX: 00007eff6758e969 RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 00007eff67610ab1 R08: 0000000000000004 R09: 0000000000000000 R10: 0000200000000140 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007eff677b5fa0 R15: 00007ffe235888a8