Warning: Permanently added '10.128.10.38' (ECDSA) to the list of known hosts. executing program [ 43.010077] [ 43.011751] ====================================================== [ 43.018041] WARNING: possible circular locking dependency detected [ 43.024420] 4.20.0+ #3 Not tainted [ 43.027931] ------------------------------------------------------ [ 43.034221] syz-executor028/7506 is trying to acquire lock: [ 43.039917] 000000004d7291a5 (&pipe->mutex/1){+.+.}, at: fifo_open+0x159/0xb00 [ 43.047261] [ 43.047261] but task is already holding lock: [ 43.053201] 000000009640b548 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds+0x55/0x120 [ 43.061952] [ 43.061952] which lock already depends on the new lock. [ 43.061952] [ 43.070324] [ 43.070324] the existing dependency chain (in reverse order) is: [ 43.077936] [ 43.077936] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 43.084242] __mutex_lock+0x12f/0x1670 [ 43.088629] mutex_lock_interruptible_nested+0x16/0x20 [ 43.094418] proc_pid_attr_write+0x1fa/0x530 [ 43.099322] __vfs_write+0x116/0xb40 [ 43.103546] __kernel_write+0x110/0x3b0 [ 43.108023] write_pipe_buf+0x180/0x240 [ 43.112525] __splice_from_pipe+0x39a/0x7e0 [ 43.117345] splice_from_pipe+0x1ea/0x310 [ 43.121996] default_file_splice_write+0x3c/0x90 [ 43.127266] do_splice+0x64b/0x1410 [ 43.131410] __x64_sys_splice+0x2c6/0x330 [ 43.136070] do_syscall_64+0x1a3/0x800 [ 43.140455] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 43.146149] [ 43.146149] -> #0 (&pipe->mutex/1){+.+.}: [ 43.151751] lock_acquire+0x1db/0x570 [ 43.156074] __mutex_lock+0x12f/0x1670 [ 43.160476] mutex_lock_nested+0x16/0x20 [ 43.165064] fifo_open+0x159/0xb00 [ 43.169111] do_dentry_open+0x48a/0x1210 [ 43.173756] vfs_open+0xa0/0xd0 [ 43.177552] path_openat+0x144f/0x5650 [ 43.181946] do_filp_open+0x26f/0x370 [ 43.186249] do_open_execat+0x20e/0x930 [ 43.190733] __do_execve_file.isra.0+0x181e/0x2510 [ 43.196170] __x64_sys_execve+0x8f/0xc0 [ 43.200641] do_syscall_64+0x1a3/0x800 [ 43.205023] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 43.210702] [ 43.210702] other info that might help us debug this: [ 43.210702] [ 43.218811] Possible unsafe locking scenario: [ 43.218811] [ 43.224953] CPU0 CPU1 [ 43.229612] ---- ---- [ 43.234250] lock(&sig->cred_guard_mutex); [ 43.238546] lock(&pipe->mutex/1); [ 43.244752] lock(&sig->cred_guard_mutex); [ 43.251648] lock(&pipe->mutex/1); [ 43.255246] [ 43.255246] *** DEADLOCK *** [ 43.255246] [ 43.261272] 1 lock held by syz-executor028/7506: [ 43.265995] #0: 000000009640b548 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds+0x55/0x120 [ 43.275158] [ 43.275158] stack backtrace: [ 43.279647] CPU: 1 PID: 7506 Comm: syz-executor028 Not tainted 4.20.0+ #3 [ 43.286546] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 43.295873] Call Trace: [ 43.298451] dump_stack+0x1db/0x2d0 [ 43.302061] ? dump_stack_print_info.cold+0x20/0x20 [ 43.307055] ? print_stack_trace+0x77/0xb0 [ 43.311299] ? vprintk_func+0x86/0x189 [ 43.315256] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 43.320591] __lock_acquire+0x3014/0x4a30 [ 43.324714] ? add_lock_to_list.isra.0+0x450/0x450 [ 43.329637] ? is_bpf_text_address+0xac/0x170 [ 43.334128] ? mark_held_locks+0x100/0x100 [ 43.338339] ? mark_held_locks+0xb1/0x100 [ 43.342468] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 43.347647] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 43.352843] ? lockdep_hardirqs_on+0x415/0x5d0 [ 43.357419] ? trace_hardirqs_off_caller+0x300/0x300 [ 43.362592] ? do_raw_spin_trylock+0x270/0x270 [ 43.367147] ? add_lock_to_list.isra.0+0x450/0x450 [ 43.372053] ? print_usage_bug+0xd0/0xd0 [ 43.376089] ? _raw_spin_unlock_irqrestore+0xa4/0xe0 [ 43.381168] ? __lock_is_held+0xb6/0x140 [ 43.385205] lock_acquire+0x1db/0x570 [ 43.388982] ? fifo_open+0x159/0xb00 [ 43.392676] ? ___might_sleep+0x1e7/0x310 [ 43.396805] ? lock_release+0xc40/0xc40 [ 43.400753] ? fifo_open+0x159/0xb00 [ 43.404441] ? fifo_open+0x159/0xb00 [ 43.408246] __mutex_lock+0x12f/0x1670 [ 43.412125] ? fifo_open+0x159/0xb00 [ 43.415836] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 43.421359] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 43.426868] ? fifo_open+0x159/0xb00 [ 43.430557] ? lockdep_init_map+0x10c/0x5b0 [ 43.434853] ? mutex_trylock+0x2d0/0x2d0 [ 43.438890] ? add_lock_to_list.isra.0+0x450/0x450 [ 43.443812] ? __mutex_init+0x1f6/0x2a0 [ 43.447760] ? psi_task_change.cold+0x1ec/0x1ec [ 43.452402] ? fifo_open+0x2b5/0xb00 [ 43.456090] ? find_held_lock+0x35/0x120 [ 43.460130] ? fifo_open+0x2b5/0xb00 [ 43.463927] ? lock_acquire+0x1db/0x570 [ 43.467882] ? kasan_check_read+0x11/0x20 [ 43.472016] ? do_raw_spin_unlock+0xa0/0x330 [ 43.476521] ? do_raw_spin_trylock+0x270/0x270 [ 43.481086] mutex_lock_nested+0x16/0x20 [ 43.485149] ? _raw_spin_unlock+0x2d/0x50 [ 43.489273] ? mutex_lock_nested+0x16/0x20 [ 43.493480] fifo_open+0x159/0xb00 [ 43.496997] do_dentry_open+0x48a/0x1210 [ 43.501080] ? pipe_release+0x280/0x280 [ 43.505070] ? chown_common+0x740/0x740 [ 43.509020] ? security_inode_permission+0xd5/0x110 [ 43.514029] ? inode_permission+0xb4/0x570 [ 43.518239] vfs_open+0xa0/0xd0 [ 43.521501] path_openat+0x144f/0x5650 [ 43.525374] ? is_bpf_text_address+0xd3/0x170 [ 43.529844] ? kernel_text_address+0x73/0xf0 [ 43.534229] ? path_lookupat.isra.0+0xba0/0xba0 [ 43.538872] ? save_stack+0xa9/0xd0 [ 43.542482] ? __lock_acquire+0x572/0x4a30 [ 43.546713] ? __x64_sys_execve+0x8f/0xc0 [ 43.550924] ? add_lock_to_list.isra.0+0x450/0x450 [ 43.555843] do_filp_open+0x26f/0x370 [ 43.559619] ? refcount_add_not_zero_checked+0x330/0x330 [ 43.565043] ? may_open_dev+0x100/0x100 [ 43.568997] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 43.574509] ? refcount_inc_checked+0x2b/0x70 [ 43.578994] ? add_lock_to_list.isra.0+0x450/0x450 [ 43.583903] ? add_lock_to_list.isra.0+0x450/0x450 [ 43.588837] ? apparmor_cred_transfer+0x5b0/0x5b0 [ 43.593654] ? prepare_creds+0xa4/0x4e0 [ 43.597603] ? prepare_creds+0xa4/0x4e0 [ 43.601551] ? __do_execve_file.isra.0+0x908/0x2510 [ 43.606538] do_open_execat+0x20e/0x930 [ 43.610488] ? unregister_binfmt+0x2b0/0x2b0 [ 43.614874] ? kasan_check_read+0x11/0x20 [ 43.618998] ? do_raw_spin_trylock+0x270/0x270 [ 43.623559] ? key_put+0x36/0x90 [ 43.626907] __do_execve_file.isra.0+0x181e/0x2510 [ 43.631833] ? prepare_bprm_creds+0x120/0x120 [ 43.636306] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 43.641817] ? strncpy_from_user+0x317/0x440 [ 43.646218] ? digsig_verify.cold+0x32/0x32 [ 43.650511] ? kmem_cache_alloc+0x341/0x710 [ 43.654817] ? do_syscall_64+0x8c/0x800 [ 43.658766] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 43.664281] ? getname_flags+0x277/0x5b0 [ 43.668362] ? trace_hardirqs_off_caller+0x300/0x300 [ 43.673453] __x64_sys_execve+0x8f/0xc0 [ 43.677402] do_syscall_64+0x1a3/0x800 [ 43.681280] ? syscall_return_slowpath+0x5f0/0x5f0 [ 43.686192] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 43.691199] ? __switch_to_asm+0x34/0x70 [ 43.695237] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 43.700070] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 43.705253] RIP: 0033:0x445729 [ 43.708426] Code: e8 6c b6 02 00 48 83 c4 18 c3 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 0f 83 2b 12 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 43.727304] RSP: 002b:00007f93d17fdda8 EFLAGS: 00000246 ORIG_RAX: 000000000000003b [ 43.734985] RAX: ffffffffffffffda RBX: 00000000006dac58 RCX: 0000000000445729 [ 43.742335] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000340 [ 43.749579] RBP: 00000000006dac50 R08: 0000000000000000 R09: 0000000000000000 [ 43.756822] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000