============================================ WARNING: possible recursive locking detected 6.4.0-rc4-syzkaller-g908f31f2a05b #0 Not tainted -------------------------------------------- syz-executor369/5974 is trying to acquire lock: ffff0000ce324c68 (&pipe->mutex/1){+.+.}-{3:3}, at: __pipe_lock fs/pipe.c:103 [inline] ffff0000ce324c68 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_write+0x108/0x19c8 fs/pipe.c:432 but task is already holding lock: ffff0000ce325068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] ffff0000ce325068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] ffff0000ce325068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x320/0x468 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-executor369/5974: #0: ffff0000ce325068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] #0: ffff0000ce325068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] #0: ffff0000ce325068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x320/0x468 fs/pipe.c:1054 stack backtrace: CPU: 1 PID: 5974 Comm: syz-executor369 Not tainted 6.4.0-rc4-syzkaller-g908f31f2a05b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 __lock_acquire+0x62b8/0x7604 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5705 __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:799 __pipe_lock fs/pipe.c:103 [inline] pipe_write+0x108/0x19c8 fs/pipe.c:432 do_iter_write+0x65c/0xa80 fs/read_write.c:860 vfs_iter_write+0x88/0xac fs/read_write.c:901 iter_file_splice_write+0x610/0xc40 fs/splice.c:795 do_splice_from fs/splice.c:873 [inline] do_splice+0x1040/0x1ba4 fs/splice.c:1182 __do_splice fs/splice.c:1260 [inline] __do_sys_splice fs/splice.c:1471 [inline] __se_sys_splice fs/splice.c:1453 [inline] __arm64_sys_splice+0x490/0x804 fs/splice.c:1453 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191 el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591