====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.5.7164/2328 is trying to acquire lock: ffff888068952088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343 but task is already holding lock: ffff88807bbae468 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline] ffff88807bbae468 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x64/0x80 fs/pipe.c:88 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&pipe->mutex){+.+.}-{4:4} : __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 anon_pipe_write+0x15d/0x1bd0 fs/pipe.c:458 __kernel_write_iter+0x720/0xb10 fs/read_write.c:619 __kernel_write+0xf5/0x140 fs/read_write.c:639 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x4db/0xd60 fs/autofs/waitq.c:164 autofs_wait+0x10f3/0x1ac0 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3c0 fs/autofs/root.c:255 autofs_d_automount+0x4b2/0x960 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x1b9/0x830 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x772/0xf50 fs/namei.c:2043 step_into fs/namei.c:2091 [inline] walk_component fs/namei.c:2227 [inline] lookup_last fs/namei.c:2722 [inline] path_lookupat+0x627/0xc40 fs/namei.c:2746 filename_lookup+0x224/0x5f0 fs/namei.c:2775 vfs_statx+0x101/0x3f0 fs/stat.c:353 vfs_fstatat fs/stat.c:375 [inline] vfs_stat include/linux/fs.h:3157 [inline] __do_sys_newstat+0xa8/0x130 fs/stat.c:515 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&sbi->pipe_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x4a6/0xd60 fs/autofs/waitq.c:164 autofs_wait+0x10f3/0x1ac0 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3c0 fs/autofs/root.c:255 autofs_d_automount+0x4b2/0x960 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x1b9/0x830 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x772/0xf50 fs/namei.c:2043 step_into fs/namei.c:2091 [inline] walk_component fs/namei.c:2227 [inline] lookup_last fs/namei.c:2722 [inline] path_lookupat+0x627/0xc40 fs/namei.c:2746 filename_lookup+0x224/0x5f0 fs/namei.c:2775 kern_path+0x35/0x50 fs/namei.c:2987 lookup_bdev+0xd8/0x280 block/bdev.c:1222 resume_store+0x1d6/0x490 kernel/power/hibernate.c:1306 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x7d3/0x11d0 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/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+0x1669/0x2890 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343 iter_file_splice_write+0xa24/0x12b0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0x1478/0x1fc0 fs/splice.c:1351 __do_splice+0x32a/0x360 fs/splice.c:1433 __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice fs/splice.c:1618 [inline] __x64_sys_splice+0x187/0x250 fs/splice.c:1618 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/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 --> &sbi->pipe_mutex --> &pipe->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex); lock(&sbi->pipe_mutex); lock(&pipe->mutex); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.5.7164/2328: #0: ffff8880358a6420 (sb_writers#8){.+.+}-{0:0}, at: __do_splice+0x32a/0x360 fs/splice.c:1433 #1: ffff88807bbae468 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline] #1: ffff88807bbae468 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x64/0x80 fs/pipe.c:88 stack backtrace: CPU: 0 UID: 0 PID: 2328 Comm: syz.5.7164 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 lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x340 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 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+0x1669/0x2890 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343 iter_file_splice_write+0xa24/0x12b0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0x1478/0x1fc0 fs/splice.c:1351 __do_splice+0x32a/0x360 fs/splice.c:1433 __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice fs/splice.c:1618 [inline] __x64_sys_splice+0x187/0x250 fs/splice.c:1618 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd6d598f749 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:00007fd6d3bf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007fd6d5be6090 RCX: 00007fd6d598f749 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007fd6d5a13f91 R08: 000000000000bfd1 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd6d5be6128 R14: 00007fd6d5be6090 R15: 00007ffdc1e2f468