============================================ WARNING: possible recursive locking detected 6.6.0-rc1-next-20230915-syzkaller #0 Not tainted -------------------------------------------- syz-executor.2/6821 is trying to acquire lock: ffff88807f308868 (&pipe->mutex/1){+.+.}-{3:3}, at: __pipe_lock fs/pipe.c:103 [inline] ffff88807f308868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_write+0x140/0x1cc0 fs/pipe.c:432 but task is already holding lock: ffff888029b66868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] ffff888029b66868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] ffff888029b66868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock+0x5e/0x70 fs/pipe.c:85 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&pipe->mutex/1); lock(&pipe->mutex/1); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by syz-executor.2/6821: #0: ffff888029b66868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] #0: ffff888029b66868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] #0: ffff888029b66868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock+0x5e/0x70 fs/pipe.c:85 stack backtrace: CPU: 1 PID: 6821 Comm: syz-executor.2 Not tainted 6.6.0-rc1-next-20230915-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3855 [inline] __lock_acquire+0x2971/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747 __pipe_lock fs/pipe.c:103 [inline] pipe_write+0x140/0x1cc0 fs/pipe.c:432 call_write_iter include/linux/fs.h:1986 [inline] do_iter_readv_writev+0x21e/0x3c0 fs/read_write.c:735 do_iter_write+0x17f/0x830 fs/read_write.c:860 vfs_iter_write+0x7a/0xb0 fs/read_write.c:901 iter_file_splice_write+0x698/0xbf0 fs/splice.c:736 do_splice_from fs/splice.c:933 [inline] do_splice+0x128a/0x1fc0 fs/splice.c:1292 __do_splice+0x323/0x360 fs/splice.c:1370 __do_sys_splice fs/splice.c:1586 [inline] __se_sys_splice fs/splice.c:1568 [inline] __x64_sys_splice+0x1ce/0x260 fs/splice.c:1568 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f763867cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f76371aa0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f763879c120 RCX: 00007f763867cae9 RDX: 000000000000000a RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f76386c847a R08: 000000000004ffe2 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f763879c120 R15: 00007ffc7f6b9718