[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 36.591302][ T26] audit: type=1800 audit(1571902926.616:25): pid=7022 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 36.611946][ T26] audit: type=1800 audit(1571902926.626:26): pid=7022 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 36.611961][ T26] audit: type=1800 audit(1571902926.626:27): pid=7022 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 '10.128.1.53' (ECDSA) to the list of known hosts. 2019/10/24 07:42:17 fuzzer started 2019/10/24 07:42:18 dialing manager at 10.128.0.105:42135 2019/10/24 07:42:18 syscalls: 2524 2019/10/24 07:42:18 code coverage: enabled 2019/10/24 07:42:18 comparison tracing: enabled 2019/10/24 07:42:18 extra coverage: extra coverage is not supported by the kernel 2019/10/24 07:42:18 setuid sandbox: enabled 2019/10/24 07:42:18 namespace sandbox: enabled 2019/10/24 07:42:18 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/24 07:42:18 fault injection: enabled 2019/10/24 07:42:18 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/24 07:42:18 net packet injection: enabled 2019/10/24 07:42:18 net device setup: enabled 2019/10/24 07:42:18 concurrency sanitizer: enabled 2019/10/24 07:42:19 adding functions to KCSAN blacklist: '__hrtimer_run_queues' 'tick_sched_do_timer' 'tick_do_update_jiffies64' 'ep_poll' syzkaller login: [ 49.143847][ T7174] ================================================================== [ 49.151972][ T7174] BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg [ 49.158966][ T7174] [ 49.161276][ T7174] write to 0xffff8881239e2138 of 8 bytes by interrupt on cpu 0: [ 49.168882][ T7174] tcp_add_backlog+0x45a/0xcc0 [ 49.173670][ T7174] tcp_v4_rcv+0x1a60/0x1bb0 [ 49.178164][ T7174] ip_protocol_deliver_rcu+0x4d/0x420 [ 49.183521][ T7174] ip_local_deliver_finish+0x110/0x140 [ 49.188970][ T7174] ip_local_deliver+0x133/0x210 [ 49.193828][ T7174] ip_rcv_finish+0x121/0x160 [ 49.198404][ T7174] ip_rcv+0x18f/0x1a0 [ 49.202362][ T7174] __netif_receive_skb_one_core+0xa7/0xe0 [ 49.208063][ T7174] __netif_receive_skb+0x37/0xf0 [ 49.212977][ T7174] netif_receive_skb_internal+0x59/0x190 [ 49.218580][ T7174] napi_gro_receive+0x28f/0x330 [ 49.223407][ T7174] receive_buf+0x284/0x30b0 [ 49.227884][ T7174] virtnet_poll+0x436/0x7d0 [ 49.232361][ T7174] net_rx_action+0x3ae/0xa90 [ 49.236920][ T7174] [ 49.239225][ T7174] read to 0xffff8881239e2138 of 8 bytes by task 7174 on cpu 1: [ 49.246741][ T7174] tcp_recvmsg+0x470/0x1a30 [ 49.251219][ T7174] inet_recvmsg+0xbb/0x250 [ 49.255613][ T7174] sock_recvmsg+0x92/0xb0 [ 49.259915][ T7174] sock_read_iter+0x15f/0x1e0 [ 49.264579][ T7174] new_sync_read+0x389/0x4f0 [ 49.269153][ T7174] __vfs_read+0xb1/0xc0 [ 49.273290][ T7174] vfs_read+0x143/0x2c0 [ 49.277437][ T7174] ksys_read+0xd5/0x1b0 [ 49.281621][ T7174] __x64_sys_read+0x4c/0x60 [ 49.286107][ T7174] do_syscall_64+0xcc/0x370 [ 49.290588][ T7174] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 49.296450][ T7174] [ 49.298760][ T7174] Reported by Kernel Concurrency Sanitizer on: [ 49.304888][ T7174] CPU: 1 PID: 7174 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 49.312315][ T7174] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 49.322345][ T7174] ================================================================== [ 49.330389][ T7174] Kernel panic - not syncing: panic_on_warn set ... [ 49.336953][ T7174] CPU: 1 PID: 7174 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 49.344392][ T7174] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 49.354430][ T7174] Call Trace: [ 49.357709][ T7174] dump_stack+0xf5/0x159 [ 49.361940][ T7174] panic+0x210/0x640 [ 49.365831][ T7174] ? __x64_sys_read+0x4c/0x60 [ 49.370493][ T7174] ? vprintk_func+0x8d/0x140 [ 49.375072][ T7174] kcsan_report.cold+0xc/0x10 [ 49.379726][ T7174] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 49.385259][ T7174] __tsan_read8+0x2c/0x30 [ 49.389567][ T7174] tcp_recvmsg+0x470/0x1a30 [ 49.394057][ T7174] inet_recvmsg+0xbb/0x250 [ 49.398448][ T7174] ? __tsan_read8+0x2c/0x30 [ 49.402937][ T7174] ? inet_sendpage+0x100/0x100 [ 49.407703][ T7174] sock_recvmsg+0x92/0xb0 [ 49.412013][ T7174] sock_read_iter+0x15f/0x1e0 [ 49.416672][ T7174] new_sync_read+0x389/0x4f0 [ 49.421504][ T7174] __vfs_read+0xb1/0xc0 [ 49.425661][ T7174] vfs_read+0x143/0x2c0 [ 49.429859][ T7174] ksys_read+0xd5/0x1b0 [ 49.434004][ T7174] __x64_sys_read+0x4c/0x60 [ 49.438664][ T7174] do_syscall_64+0xcc/0x370 [ 49.443180][ T7174] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 49.449057][ T7174] RIP: 0033:0x47c530 [ 49.452935][ T7174] Code: 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 49 c7 c2 00 00 00 00 49 c7 c0 00 00 00 00 49 c7 c1 00 00 00 00 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 30 [ 49.472560][ T7174] RSP: 002b:000000c4200517d8 EFLAGS: 00000212 ORIG_RAX: 0000000000000000 [ 49.480958][ T7174] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 49.488914][ T7174] RDX: 0000000000001000 RSI: 000000c420308000 RDI: 0000000000000003 [ 49.497314][ T7174] RBP: 000000c420051830 R08: 0000000000000000 R09: 0000000000000000 [ 49.505265][ T7174] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000008 [ 49.513214][ T7174] R13: ffffffffffffffff R14: 0000000000000020 R15: ffffffffffffffff [ 49.522571][ T7174] Kernel Offset: disabled [ 49.526889][ T7174] Rebooting in 86400 seconds..