====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.9.13999/5382 is trying to acquire lock: ffff88803b794128 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] ffff88803b794128 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x70e/0xe20 fs/autofs/waitq.c:164 but task is already holding lock: ffff888032690478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 iter_file_splice_write+0x977/0x10b0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0xc8e/0x1680 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 -> #1 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 anon_pipe_write+0x160/0x1460 fs/pipe.c:458 __kernel_write_iter+0x48a/0x920 fs/read_write.c:619 __kernel_write+0xef/0x150 fs/read_write.c:639 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x721/0xe20 fs/autofs/waitq.c:164 autofs_wait+0x11f7/0x1900 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64f/0x820 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x469/0x7d0 fs/namei.c:2043 step_into fs/namei.c:2091 [inline] open_last_lookups fs/namei.c:4575 [inline] path_openat+0x27c0/0x3df0 fs/namei.c:4784 do_filp_open+0x1fa/0x410 fs/namei.c:4814 do_sys_openat2+0x121/0x200 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 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 (&sbi->pipe_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/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x70e/0xe20 fs/autofs/waitq.c:164 autofs_wait+0x11f7/0x1900 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64f/0x820 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x469/0x7d0 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+0x433/0x8c0 fs/namei.c:2746 filename_lookup+0x212/0x570 fs/namei.c:2775 kern_path+0x35/0x50 fs/namei.c:2987 lookup_bdev+0xc0/0x280 block/bdev.c:1222 resume_store+0x169/0x480 kernel/power/hibernate.c:1306 kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5d5/0xb40 fs/read_write.c:686 ksys_write+0x14b/0x260 fs/read_write.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 other info that might help us debug this: Chain exists of: &sbi->pipe_mutex --> &pipe->mutex --> &of->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&of->mutex); lock(&pipe->mutex); lock(&of->mutex); lock(&sbi->pipe_mutex); *** DEADLOCK *** 4 locks held by syz.9.13999/5382: #0: ffff88803c865b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x253/0x320 fs/file.c:1255 #1: ffff8880307e0480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #1: ffff8880307e0480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #2: ffff888032690478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #3: ffff88801c694788 (kn->active#94){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #3: ffff88801c694788 (kn->active#94){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 stack backtrace: CPU: 1 UID: 0 PID: 5382 Comm: syz.9.13999 Tainted: G L syzkaller #0 PREEMPT_{RT,(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/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x70e/0xe20 fs/autofs/waitq.c:164 autofs_wait+0x11f7/0x1900 fs/autofs/waitq.c:426 autofs_mount_wait+0x16b/0x390 fs/autofs/root.c:255 autofs_d_automount+0x64f/0x820 fs/autofs/root.c:409 follow_automount fs/namei.c:1499 [inline] __traverse_mounts+0x301/0x5e0 fs/namei.c:1552 traverse_mounts fs/namei.c:1581 [inline] handle_mounts fs/namei.c:1686 [inline] step_into_slowpath+0x469/0x7d0 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+0x433/0x8c0 fs/namei.c:2746 filename_lookup+0x212/0x570 fs/namei.c:2775 kern_path+0x35/0x50 fs/namei.c:2987 lookup_bdev+0xc0/0x280 block/bdev.c:1222 resume_store+0x169/0x480 kernel/power/hibernate.c:1306 kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5d5/0xb40 fs/read_write.c:686 ksys_write+0x14b/0x260 fs/read_write.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 RIP: 0033:0x7ffab507f749 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:00007ffab32de038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007ffab52d5fa0 RCX: 00007ffab507f749 RDX: 0000000000000012 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007ffab5103f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffab52d6038 R14: 00007ffab52d5fa0 R15: 00007ffc1ecd80c8 PM: Image not found (code -22)