============================================ WARNING: possible recursive locking detected 6.3.0-syzkaller-00113-g1a0beef98b58 #0 Not tainted -------------------------------------------- syz-executor.0/30679 is trying to acquire lock: ffff88804bd1bc68 (&pipe->mutex/1){+.+.}-{3:3}, at: __pipe_lock fs/pipe.c:103 [inline] ffff88804bd1bc68 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_write+0x136/0x1c20 fs/pipe.c:431 but task is already holding lock: ffff88804cabf068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] ffff88804cabf068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] ffff88804cabf068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x39f/0x420 fs/pipe.c:1049 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.0/30679: #0: ffff88804cabf068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock_nested fs/pipe.c:82 [inline] #0: ffff88804cabf068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:90 [inline] #0: ffff88804cabf068 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_wait_readable+0x39f/0x420 fs/pipe.c:1049 stack backtrace: CPU: 1 PID: 30679 Comm: syz-executor.0 Not tainted 6.3.0-syzkaller-00113-g1a0beef98b58 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 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:2991 [inline] check_deadlock kernel/locking/lockdep.c:3034 [inline] validate_chain kernel/locking/lockdep.c:3819 [inline] __lock_acquire+0x1362/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire kernel/locking/lockdep.c:5669 [inline] lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634 __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+0x136/0x1c20 fs/pipe.c:431 call_write_iter include/linux/fs.h:1851 [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:778 do_splice_from fs/splice.c:856 [inline] do_splice+0xb5b/0x1960 fs/splice.c:1165 __do_splice+0x134/0x250 fs/splice.c:1230 __do_sys_splice fs/splice.c:1437 [inline] __se_sys_splice fs/splice.c:1419 [inline] __ia32_sys_splice+0x199/0x250 fs/splice.c:1419 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f08579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7f035cc EFLAGS: 00000296 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000000000 RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 retq 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi