Warning: Permanently added '10.128.0.189' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 51.399814] [ 51.401493] ====================================================== [ 51.407785] WARNING: possible circular locking dependency detected [ 51.414078] 5.0.0-rc7+ #78 Not tainted [ 51.417957] ------------------------------------------------------ [ 51.424258] syz-executor196/7931 is trying to acquire lock: [ 51.429944] 00000000a5a6074f (&sig->cred_guard_mutex){+.+.}, at: proc_pid_attr_write+0x1fa/0x530 [ 51.438877] [ 51.438877] but task is already holding lock: [ 51.444834] 00000000574aa395 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 51.452035] [ 51.452035] which lock already depends on the new lock. [ 51.452035] [ 51.460324] [ 51.460324] the existing dependency chain (in reverse order) is: [ 51.467933] [ 51.467933] -> #1 (&pipe->mutex/1){+.+.}: [ 51.473568] __mutex_lock+0xf7/0x1310 [ 51.477883] mutex_lock_nested+0x16/0x20 [ 51.482456] fifo_open+0x159/0xb00 [ 51.486502] do_dentry_open+0x47d/0x1130 [ 51.491064] vfs_open+0xa0/0xd0 [ 51.494843] path_openat+0x10d7/0x4690 [ 51.499469] do_filp_open+0x1a1/0x280 [ 51.503774] do_open_execat+0x13b/0x6d0 [ 51.508252] __do_execve_file.isra.0+0x178d/0x23f0 [ 51.513689] __x64_sys_execve+0x8f/0xc0 [ 51.518170] do_syscall_64+0x103/0x610 [ 51.522563] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.528248] [ 51.528248] -> #0 (&sig->cred_guard_mutex){+.+.}: [ 51.534556] lock_acquire+0x16f/0x3f0 [ 51.538862] __mutex_lock+0xf7/0x1310 [ 51.543186] mutex_lock_interruptible_nested+0x16/0x20 [ 51.548974] proc_pid_attr_write+0x1fa/0x530 [ 51.553886] __vfs_write+0x116/0x8e0 [ 51.558107] __kernel_write+0x110/0x3b0 [ 51.562601] write_pipe_buf+0x15d/0x1f0 [ 51.567099] __splice_from_pipe+0x39a/0x7e0 [ 51.571938] splice_from_pipe+0x108/0x170 [ 51.576602] default_file_splice_write+0x3c/0x90 [ 51.581868] do_splice+0x644/0x1330 [ 51.586011] __x64_sys_splice+0x2c6/0x330 [ 51.590674] do_syscall_64+0x103/0x610 [ 51.595083] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.600780] [ 51.600780] other info that might help us debug this: [ 51.600780] [ 51.608909] Possible unsafe locking scenario: [ 51.608909] [ 51.614961] CPU0 CPU1 [ 51.619615] ---- ---- [ 51.624266] lock(&pipe->mutex/1); [ 51.627890] lock(&sig->cred_guard_mutex); [ 51.634718] lock(&pipe->mutex/1); [ 51.640854] lock(&sig->cred_guard_mutex); [ 51.645164] [ 51.645164] *** DEADLOCK *** [ 51.645164] [ 51.651217] 2 locks held by syz-executor196/7931: [ 51.656043] #0: 000000001a854dbf (sb_writers#6){.+.+}, at: do_splice+0xceb/0x1330 [ 51.663764] #1: 00000000574aa395 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 51.671401] [ 51.671401] stack backtrace: [ 51.675901] CPU: 0 PID: 7931 Comm: syz-executor196 Not tainted 5.0.0-rc7+ #78 [ 51.683160] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.692510] Call Trace: [ 51.695102] dump_stack+0x172/0x1f0 [ 51.698729] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 51.704093] __lock_acquire+0x2f00/0x4700 [ 51.708235] ? trace_hardirqs_on+0x67/0x230 [ 51.712557] ? kasan_check_read+0x11/0x20 [ 51.716708] ? mark_held_locks+0x100/0x100 [ 51.720938] ? __kmalloc_track_caller+0x158/0x740 [ 51.725779] ? memdup_user+0x26/0xb0 [ 51.729489] ? proc_pid_attr_write+0x196/0x530 [ 51.734072] ? __vfs_write+0x116/0x8e0 [ 51.737952] ? __kernel_write+0x110/0x3b0 [ 51.742095] ? write_pipe_buf+0x15d/0x1f0 [ 51.746242] ? __splice_from_pipe+0x39a/0x7e0 [ 51.750737] ? __lock_is_held+0xb6/0x140 [ 51.754799] ? proc_pid_attr_write+0x1fa/0x530 [ 51.759396] lock_acquire+0x16f/0x3f0 [ 51.763212] ? proc_pid_attr_write+0x1fa/0x530 [ 51.767793] ? proc_pid_attr_write+0x1fa/0x530 [ 51.772378] __mutex_lock+0xf7/0x1310 [ 51.776183] ? proc_pid_attr_write+0x1fa/0x530 [ 51.780760] ? proc_pid_attr_write+0x1fa/0x530 [ 51.785353] ? check_preemption_disabled+0x48/0x290 [ 51.790361] ? mutex_trylock+0x1e0/0x1e0 [ 51.794419] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 51.799882] ? check_stack_object+0x114/0x160 [ 51.804369] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.809904] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.815451] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.820983] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.826518] ? _copy_from_user+0xdd/0x150 [ 51.830664] mutex_lock_interruptible_nested+0x16/0x20 [ 51.835937] ? mutex_lock_interruptible_nested+0x16/0x20 [ 51.841401] proc_pid_attr_write+0x1fa/0x530 [ 51.845852] __vfs_write+0x116/0x8e0 [ 51.849562] ? proc_loginuid_write+0x4d0/0x4d0 [ 51.854144] ? kernel_read+0x120/0x120 [ 51.858033] ? lock_pi_update_atomic+0x120/0x120 [ 51.862816] ? __lock_is_held+0xb6/0x140 [ 51.866867] ? lock_acquire+0x16f/0x3f0 [ 51.870864] __kernel_write+0x110/0x3b0 [ 51.874844] write_pipe_buf+0x15d/0x1f0 [ 51.878818] ? do_splice_direct+0x2a0/0x2a0 [ 51.883134] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 51.888668] ? splice_from_pipe_next.part.0+0x255/0x2f0 [ 51.894033] __splice_from_pipe+0x39a/0x7e0 [ 51.898350] ? do_splice_direct+0x2a0/0x2a0 [ 51.902673] ? do_splice_direct+0x2a0/0x2a0 [ 51.907000] splice_from_pipe+0x108/0x170 [ 51.911146] ? splice_shrink_spd+0xd0/0xd0 [ 51.915384] ? __lock_is_held+0xb6/0x140 [ 51.919450] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 51.924902] default_file_splice_write+0x3c/0x90 [ 51.929649] ? generic_splice_sendpage+0x50/0x50 [ 51.934401] do_splice+0x644/0x1330 [ 51.938028] ? iterate_fd+0x360/0x360 [ 51.941829] ? opipe_prep.part.0+0x2d0/0x2d0 [ 51.946245] ? __fget_light+0x1a9/0x230 [ 51.950213] __x64_sys_splice+0x2c6/0x330 [ 51.954364] do_syscall_64+0x103/0x610 [ 51.958253] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.963442] RIP: 0033:0x445779 [ 51.966635] 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 [ 51.985552] RSP: 002b:00007f65e6ea5da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 [ 51.993254] RAX: ffffffffffffffda RBX: 00000000006dac68 RCX: 0000000000445779 [ 52.000517] RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003 [ 52.007781] RBP: 00000000006dac60 R08: 0000020000000003 R09: 0000000000000009 [ 52.015056] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac6c [ 52.022315] R13: 00007ffc5e8f7d8f R14: 00007f65e6ea69c0 R15: 20c49ba5e353f7cf