./strace-static-x86_64 -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f ./syz-executor3095885782 <...> Warning: Permanently added '10.128.1.228' (ED25519) to the list of known hosts. execve("./syz-executor3095885782", ["./syz-executor3095885782"], 0x7ffcb558c6c0 /* 10 vars */) = 0 brk(NULL) = 0x55555f26e000 brk(0x55555f26ed00) = 0x55555f26ed00 arch_prctl(ARCH_SET_FS, 0x55555f26e380) = 0 set_tid_address(0x55555f26e650) = 5837 set_robust_list(0x55555f26e660, 24) = 0 rseq(0x55555f26eca0, 0x20, 0, 0x53053053) = 0 prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0 readlink("/proc/self/exe", "/root/syz-executor3095885782", 4096) = 28 getrandom("\x85\x63\x0b\xf5\x20\x94\x6b\xcb", 8, GRND_NONBLOCK) = 8 brk(NULL) = 0x55555f26ed00 brk(0x55555f28fd00) = 0x55555f28fd00 brk(0x55555f290000) = 0x55555f290000 mprotect(0x7f8f7dc3b000, 16384, PROT_READ) = 0 mmap(0x1ffffffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffffffff000 mmap(0x200000000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x200000000000 mmap(0x200001000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x200001000000 executing program write(1, "executing program\n", 18) = 18 creat("./file0", 004) = 3 [ 72.020271][ T5837] [ 72.022613][ T5837] ============================================ [ 72.028736][ T5837] WARNING: possible recursive locking detected [ 72.034864][ T5837] 6.16.0-rc4-next-20250702-syzkaller #0 Not tainted [ 72.041418][ T5837] -------------------------------------------- [ 72.047535][ T5837] syz-executor309/5837 is trying to acquire lock: [ 72.053915][ T5837] ffff88807f5bc8c8 (&sb->s_type->i_mutex_key#15){+.+.}-{4:4}, at: rpc_close_pipes+0x10a/0x730 [ 72.064166][ T5837] [ 72.064166][ T5837] but task is already holding lock: [ 72.071496][ T5837] ffff88807f5b91c8 (&sb->s_type->i_mutex_key#15){+.+.}-{4:4}, at: __simple_recursive_removal+0x190/0x510 [ 72.082687][ T5837] [ 72.082687][ T5837] other info that might help us debug this: [ 72.090717][ T5837] Possible unsafe locking scenario: [ 72.090717][ T5837] [ 72.098136][ T5837] CPU0 [ 72.101386][ T5837] ---- [ 72.104641][ T5837] lock(&sb->s_type->i_mutex_key#15); [ 72.110074][ T5837] lock(&sb->s_type->i_mutex_key#15); [ 72.115505][ T5837] [ 72.115505][ T5837] *** DEADLOCK *** [ 72.115505][ T5837] [ 72.123618][ T5837] May be due to missing lock nesting notation [ 72.123618][ T5837] [ 72.131906][ T5837] 4 locks held by syz-executor309/5837: [ 72.137416][ T5837] #0: ffff888033ee40e0 (&type->s_umount_key#42){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 [ 72.147564][ T5837] #1: ffff8881446f60a0 (&sn->pipefs_sb_lock){+.+.}-{4:4}, at: rpc_kill_sb+0x77/0x190 [ 72.157093][ T5837] #2: ffffffff8f8e2df0 ((rpc_pipefs_notifier_list).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90 [ 72.169139][ T5837] #3: ffff88807f5b91c8 (&sb->s_type->i_mutex_key#15){+.+.}-{4:4}, at: __simple_recursive_removal+0x190/0x510 [ 72.180763][ T5837] [ 72.180763][ T5837] stack backtrace: [ 72.186631][ T5837] CPU: 0 UID: 0 PID: 5837 Comm: syz-executor309 Not tainted 6.16.0-rc4-next-20250702-syzkaller #0 PREEMPT(full) [ 72.186642][ T5837] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 [ 72.186654][ T5837] Call Trace: [ 72.186659][ T5837] [ 72.186664][ T5837] dump_stack_lvl+0x189/0x250 [ 72.186676][ T5837] ? __pfx_dump_stack_lvl+0x10/0x10 [ 72.186686][ T5837] ? __pfx__printk+0x10/0x10 [ 72.186696][ T5837] ? print_lock_name+0xde/0x100 [ 72.186706][ T5837] print_deadlock_bug+0x28b/0x2a0 [ 72.186716][ T5837] validate_chain+0x1a3f/0x2140 [ 72.186729][ T5837] __lock_acquire+0xab9/0xd20 [ 72.186744][ T5837] ? rpc_close_pipes+0x10a/0x730 [ 72.186752][ T5837] lock_acquire+0x120/0x360 [ 72.186764][ T5837] ? rpc_close_pipes+0x10a/0x730 [ 72.186774][ T5837] down_write+0x96/0x1f0 [ 72.186788][ T5837] ? rpc_close_pipes+0x10a/0x730 [ 72.186800][ T5837] ? __pfx_down_write+0x10/0x10 [ 72.186812][ T5837] ? __pfx_find_submount+0x10/0x10 [ 72.186820][ T5837] ? _raw_spin_unlock+0x28/0x50 [ 72.186829][ T5837] ? d_walk+0x6f4/0x780 [ 72.186842][ T5837] rpc_close_pipes+0x10a/0x730 [ 72.186850][ T5837] ? d_invalidate+0x204/0x260 [ 72.186858][ T5837] ? __pfx_rpc_close_pipes+0x10/0x10 [ 72.186867][ T5837] ? up_write+0x1c4/0x420 [ 72.186876][ T5837] ? __pfx_rpc_close_pipes+0x10/0x10 [ 72.186884][ T5837] __simple_recursive_removal+0x208/0x510 [ 72.186896][ T5837] ? __pfx_rpc_close_pipes+0x10/0x10 [ 72.186904][ T5837] rpc_unlink+0x56/0x80 [ 72.186912][ T5837] rpc_pipefs_event+0xc0/0x170 [ 72.186925][ T5837] notifier_call_chain+0x1b3/0x3e0 [ 72.186936][ T5837] blocking_notifier_call_chain+0x6a/0x90 [ 72.186945][ T5837] rpc_kill_sb+0xd0/0x190 [ 72.186956][ T5837] deactivate_locked_super+0xb9/0x130 [ 72.186965][ T5837] cleanup_mnt+0x425/0x4c0 [ 72.186974][ T5837] ? lockdep_hardirqs_on+0x9c/0x150 [ 72.186986][ T5837] task_work_run+0x1d1/0x260 [ 72.186998][ T5837] ? __pfx_task_work_run+0x10/0x10 [ 72.187009][ T5837] ? lockdep_hardirqs_on+0x9c/0x150 [ 72.187021][ T5837] ptrace_notify+0x281/0x2c0 [ 72.187036][ T5837] ? __pfx_ptrace_notify+0x10/0x10 [ 72.187048][ T5837] ? __se_sys_mount+0x3c8/0x410 [ 72.187061][ T5837] ? __pfx___se_sys_mount+0x10/0x10 [ 72.187074][ T5837] syscall_exit_work+0xc6/0x1d0 [ 72.187093][ T5837] do_syscall_64+0x2ad/0x3b0 [ 72.187106][ T5837] ? lockdep_hardirqs_on+0x9c/0x150 [ 72.187116][ T5837] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 72.187124][ T5837] ? clear_bhb_loop+0x60/0xb0 [ 72.187134][ T5837] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 72.187142][ T5837] RIP: 0033:0x7f8f7dbc82e9 [ 72.187157][ T5837] Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48 [ 72.187164][ T5837] RSP: 002b:00007ffe287838a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 [ 72.187174][ T5837] RAX: ffffffffffffffec RBX: 0000200000000000 RCX: 00007f8f7dbc82e9 mount(NULL, "./file0", "rpc_pipefs", 0, NULL) = -1 ENOTDIR (Not a directory) exit_group(0) = ? +++ exited with 0 +++ [ 72.187181][ T5837