[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 41.793742][ T25] audit: type=1800 audit(1571790002.841:25): pid=6995 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 41.813679][ T25] audit: type=1800 audit(1571790002.841:26): pid=6995 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 41.835540][ T25] audit: type=1800 audit(1571790002.841:27): pid=6995 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2469 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.247' (ECDSA) to the list of known hosts. 2019/10/23 00:20:14 fuzzer started 2019/10/23 00:20:15 dialing manager at 10.128.0.105:33369 2019/10/23 00:20:15 syscalls: 2524 2019/10/23 00:20:15 code coverage: enabled 2019/10/23 00:20:15 comparison tracing: enabled 2019/10/23 00:20:15 extra coverage: extra coverage is not supported by the kernel 2019/10/23 00:20:15 setuid sandbox: enabled 2019/10/23 00:20:15 namespace sandbox: enabled 2019/10/23 00:20:15 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/23 00:20:15 fault injection: enabled 2019/10/23 00:20:15 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/23 00:20:15 net packet injection: enabled 2019/10/23 00:20:15 net device setup: enabled 2019/10/23 00:20:15 concurrency sanitizer: enabled syzkaller login: [ 55.393808][ C0] ================================================================== [ 55.401935][ C0] BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg [ 55.408946][ C0] [ 55.411276][ C0] read to 0xffff888125db32f8 of 8 bytes by task 7151 on cpu 1: [ 55.418891][ C0] tcp_recvmsg+0x470/0x1a30 [ 55.423380][ C0] inet_recvmsg+0xbb/0x250 [ 55.427793][ C0] sock_recvmsg+0x92/0xb0 [ 55.432109][ C0] sock_read_iter+0x15f/0x1e0 [ 55.436769][ C0] new_sync_read+0x389/0x4f0 [ 55.441344][ C0] __vfs_read+0xb1/0xc0 [ 55.445481][ C0] vfs_read+0x143/0x2c0 [ 55.449621][ C0] ksys_read+0xd5/0x1b0 [ 55.453778][ C0] __x64_sys_read+0x4c/0x60 [ 55.458266][ C0] do_syscall_64+0xcc/0x370 [ 55.462766][ C0] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 55.468644][ C0] [ 55.470968][ C0] write to 0xffff888125db32f8 of 8 bytes by interrupt on cpu 0: [ 55.478584][ C0] tcp_add_backlog+0x45a/0xcc0 [ 55.483331][ C0] tcp_v4_rcv+0x1a60/0x1bb0 [ 55.487857][ C0] ip_protocol_deliver_rcu+0x4d/0x420 [ 55.493213][ C0] ip_local_deliver_finish+0x110/0x140 [ 55.498652][ C0] ip_local_deliver+0x133/0x210 [ 55.503523][ C0] ip_rcv_finish+0x121/0x160 [ 55.508105][ C0] ip_rcv+0x18f/0x1a0 [ 55.512095][ C0] __netif_receive_skb_one_core+0xa7/0xe0 [ 55.517806][ C0] __netif_receive_skb+0x37/0xf0 [ 55.522734][ C0] netif_receive_skb_internal+0x59/0x190 [ 55.528376][ C0] napi_gro_receive+0x28f/0x330 [ 55.533223][ C0] receive_buf+0x284/0x30b0 [ 55.537715][ C0] virtnet_poll+0x436/0x7d0 [ 55.542194][ C0] [ 55.544503][ C0] Reported by Kernel Concurrency Sanitizer on: [ 55.550644][ C0] CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.4.0-rc3+ #0 [ 55.557994][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.568031][ C0] ================================================================== [ 55.576084][ C0] Kernel panic - not syncing: panic_on_warn set ... [ 55.582655][ C0] CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.4.0-rc3+ #0 [ 55.589927][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.599962][ C0] Call Trace: [ 55.603247][ C0] dump_stack+0xf5/0x159 [ 55.607475][ C0] panic+0x210/0x640 [ 55.611360][ C0] ? __netif_receive_skb+0x37/0xf0 [ 55.616459][ C0] ? vprintk_func+0x8d/0x140 [ 55.621038][ C0] kcsan_report.cold+0xc/0x10 [ 55.625717][ C0] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 55.631267][ C0] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 55.636988][ C0] __tsan_write8+0x32/0x40 [ 55.641413][ C0] tcp_add_backlog+0x45a/0xcc0 [ 55.646171][ C0] tcp_v4_rcv+0x1a60/0x1bb0 [ 55.650660][ C0] ? __tsan_read8+0x2c/0x30 [ 55.655157][ C0] ip_protocol_deliver_rcu+0x4d/0x420 [ 55.660517][ C0] ip_local_deliver_finish+0x110/0x140 [ 55.665970][ C0] ip_local_deliver+0x133/0x210 [ 55.670806][ C0] ? ip_protocol_deliver_rcu+0x420/0x420 [ 55.676435][ C0] ip_rcv_finish+0x121/0x160 [ 55.681011][ C0] ip_rcv+0x18f/0x1a0 [ 55.684981][ C0] ? ip_sublist_rcv+0x5e0/0x5e0 [ 55.692000][ C0] ? ip_local_deliver+0x210/0x210 [ 55.697008][ C0] __netif_receive_skb_one_core+0xa7/0xe0 [ 55.702717][ C0] __netif_receive_skb+0x37/0xf0 [ 55.707640][ C0] netif_receive_skb_internal+0x59/0x190 [ 55.713259][ C0] napi_gro_receive+0x28f/0x330 [ 55.718097][ C0] receive_buf+0x284/0x30b0 [ 55.722596][ C0] ? __tsan_write8+0x32/0x40 [ 55.727278][ C0] ? virtqueue_get_buf_ctx+0x4fd/0x5c0 [ 55.732717][ C0] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 55.738331][ C0] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 55.743950][ C0] virtnet_poll+0x436/0x7d0 [ 55.748542][ C0] ? __sanitizer_cov_trace_cmp2+0x18/0x20 [ 55.754260][ C0] net_rx_action+0x3ae/0xa90 [ 55.758857][ C0] __do_softirq+0x115/0x33f [ 55.763356][ C0] ? takeover_tasklets+0x250/0x250 [ 55.768451][ C0] run_ksoftirqd+0x46/0x60 [ 55.772866][ C0] smpboot_thread_fn+0x37d/0x4a0 [ 55.777794][ C0] kthread+0x1d4/0x200 [ 55.781849][ C0] ? constant_test_bit.constprop.0+0x30/0x30 [ 55.787824][ C0] ? kthread_stop+0x2d0/0x2d0 [ 55.792486][ C0] ret_from_fork+0x1f/0x30 [ 55.798149][ C0] Kernel Offset: disabled [ 55.802468][ C0] Rebooting in 86400 seconds..