====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.9.4471/21936 is trying to acquire lock: ffff888058d90088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 but task is already holding lock: ffff888035d71868 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x1e3/0x10b0 fs/splice.c:683 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x184/0x1300 kernel/locking/mutex.c:776 iter_file_splice_write+0x1e3/0x10b0 fs/splice.c:683 do_splice_from fs/splice.c:938 [inline] do_splice+0xc79/0x1660 fs/splice.c:1351 __do_splice fs/splice.c:1433 [inline] __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice+0x2e1/0x460 fs/splice.c:1618 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (sb_writers#5){.+.+}-{0:0}: 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+0x4d/0x1c0 include/linux/fs/super.h:125 mnt_want_write+0x41/0x90 fs/namespace.c:504 ovl_xattr_set+0x14a/0x5d0 fs/overlayfs/xattrs.c:61 ovl_own_xattr_set+0x8b/0xb0 fs/overlayfs/xattrs.c:204 __vfs_setxattr+0x43c/0x480 fs/xattr.c:200 __vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234 vfs_setxattr+0x162/0x360 fs/xattr.c:321 do_setxattr fs/xattr.c:636 [inline] filename_setxattr+0x286/0x610 fs/xattr.c:664 path_setxattrat+0x364/0x3a0 fs/xattr.c:708 __do_sys_setxattr fs/xattr.c:742 [inline] __se_sys_setxattr fs/xattr.c:738 [inline] __x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: down_read+0x47/0x2e0 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:1043 [inline] lookup_slow+0x46/0x70 fs/namei.c:1932 walk_component fs/namei.c:2279 [inline] lookup_last fs/namei.c:2780 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2804 filename_lookup+0x212/0x570 fs/namei.c:2833 kern_path+0x3d/0x150 fs/namei.c:3040 lookup_bdev+0xc0/0x280 block/bdev.c:1222 resume_store+0x169/0x480 kernel/power/hibernate.c:1306 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:688 ksys_write+0x145/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 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:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x184/0x1300 kernel/locking/mutex.c:776 kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 iter_file_splice_write+0x972/0x10b0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0xc79/0x1660 fs/splice.c:1351 __do_splice fs/splice.c:1433 [inline] __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice+0x2e1/0x460 fs/splice.c:1618 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 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 --> sb_writers#5 --> &pipe->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex); lock(sb_writers#5); lock(&pipe->mutex); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.9.4471/21936: #0: ffff88807d25a420 (sb_writers#10){.+.+}-{0:0}, at: do_splice+0xbff/0x1660 fs/splice.c:1350 #1: ffff888035d71868 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x1e3/0x10b0 fs/splice.c:683 stack backtrace: CPU: 1 UID: 0 PID: 21936 Comm: syz.9.4471 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x184/0x1300 kernel/locking/mutex.c:776 kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 iter_file_splice_write+0x972/0x10b0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0xc79/0x1660 fs/splice.c:1351 __do_splice fs/splice.c:1433 [inline] __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice+0x2e1/0x460 fs/splice.c:1618 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe75538f749 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:00007fe756272038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007fe7555e5fa0 RCX: 00007fe75538f749 RDX: 000000000000000f RSI: 0000000000000000 RDI: 000000000000000b RBP: 00007fe755413f91 R08: 0000000000000047 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe7555e6038 R14: 00007fe7555e5fa0 R15: 00007ffe86b43c18