============================================ WARNING: possible recursive locking detected 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 Not tainted -------------------------------------------- syz-executor318/5002 is trying to acquire lock: ffff88802838d068 (&pipe->mutex/1){+.+.}-{3:3}, at: __pipe_lock fs/pipe.c:103 [inline] ffff88802838d068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_write+0x140/0x1ca0 fs/pipe.c:432 but task is already holding lock: ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x39f/0x420 fs/pipe.c:1054 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-executor318/5002: #0: ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] #0: ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] #0: ffff88802838c068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x39f/0x420 fs/pipe.c:1054 stack backtrace: CPU: 1 PID: 5002 Comm: syz-executor318 Not tainted 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:3006 [inline] check_deadlock kernel/locking/lockdep.c:3049 [inline] validate_chain kernel/locking/lockdep.c:3834 [inline] __lock_acquire+0x13eb/0x5f30 kernel/locking/lockdep.c:5088 lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5670 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747 __pipe_lock fs/pipe.c:103 [inline] pipe_write+0x140/0x1ca0 fs/pipe.c:432 call_write_iter include/linux/fs.h:1868 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x185/0x7e0 fs/read_write.c:860 vfs_iter_write+0x74/0xa0 fs/read_write.c:901 iter_file_splice_write+0x743/0xc80 fs/splice.c:795 do_splice_from fs/splice.c:873 [inline] do_splice+0xb8c/0x1e50 fs/splice.c:1182 __do_splice+0x14e/0x270 fs/splice.c:1260 __do_sys_splice fs/splice.c:1471 [inline] __se_sys_splice fs/splice.c:1453 [inline] __x64_sys_splice+0x19c/0x250 fs/splice.c:1453 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f15940e4079 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 14 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1594096278 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f159416c408 RCX: 00007f15940e4079 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007f159416c400 R08: 0000000000000100 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f159413a040 R13: 00007f1594096290 R14: 00007f1594096400 R15: 0000000000022000