====================================================== WARNING: possible circular locking dependency detected 6.15.0-rc2-syzkaller-00257-gb5c6891b2c5b #0 Not tainted ------------------------------------------------------ syz.7.1340/11516 is trying to acquire lock: ffff888059ae5088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e2/0x510 fs/kernfs/file.c:325 but task is already holding lock: ffff88807e144068 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x322/0x1530 fs/splice.c:683 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&pipe->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 anon_pipe_write+0x167/0x14f0 fs/pipe.c:459 __kernel_write_iter+0x4c0/0x990 fs/read_write.c:617 __kernel_write+0x122/0x180 fs/read_write.c:637 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x87e/0x1100 fs/autofs/waitq.c:164 autofs_wait+0x1324/0x1dd0 fs/autofs/waitq.c:426 autofs_mount_wait+0x170/0x330 fs/autofs/root.c:255 autofs_d_automount+0x555/0x710 fs/autofs/root.c:401 follow_automount fs/namei.c:1455 [inline] __traverse_mounts+0x2b5/0x580 fs/namei.c:1500 traverse_mounts fs/namei.c:1529 [inline] handle_mounts fs/namei.c:1632 [inline] step_into+0x5bd/0x1000 fs/namei.c:1966 lookup_last fs/namei.c:2626 [inline] path_lookupat+0x169/0x440 fs/namei.c:2650 filename_lookup+0x290/0x670 fs/namei.c:2679 kern_path+0x35/0x50 fs/namei.c:2787 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 -> #1 (&sbi->pipe_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 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x86b/0x1100 fs/autofs/waitq.c:164 autofs_wait+0x1324/0x1dd0 fs/autofs/waitq.c:426 autofs_mount_wait+0x170/0x330 fs/autofs/root.c:255 autofs_d_automount+0x555/0x710 fs/autofs/root.c:401 follow_automount fs/namei.c:1455 [inline] __traverse_mounts+0x2b5/0x580 fs/namei.c:1500 traverse_mounts fs/namei.c:1529 [inline] handle_mounts fs/namei.c:1632 [inline] step_into+0x5bd/0x1000 fs/namei.c:1966 lookup_last fs/namei.c:2626 [inline] path_lookupat+0x169/0x440 fs/namei.c:2650 filename_lookup+0x290/0x670 fs/namei.c:2679 kern_path+0x35/0x50 fs/namei.c:2787 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 -> #0 (&of->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 kernfs_fop_write_iter+0x1e2/0x510 fs/kernfs/file.c:325 iter_file_splice_write+0xbdf/0x1530 fs/splice.c:738 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: &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.7.1340/11516: #0: ffff888032c72420 (sb_writers#7){.+.+}-{0:0}, at: do_splice+0xd1f/0x1920 fs/splice.c:1347 #1: ffff88807e144068 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x322/0x1530 fs/splice.c:683 stack backtrace: CPU: 0 UID: 0 PID: 11516 Comm: syz.7.1340 Not tainted 6.15.0-rc2-syzkaller-00257-gb5c6891b2c5b #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 kernfs_fop_write_iter+0x1e2/0x510 fs/kernfs/file.c:325 iter_file_splice_write+0xbdf/0x1530 fs/splice.c:738 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: 0033:0x7fddbd38e169 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:00007fddbe249038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007fddbd5b6080 RCX: 00007fddbd38e169 RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007fddbd410a68 R08: 000000000000bfd1 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fddbd5b6080 R15: 00007fff72ea26b8