[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 35.085411][ T26] audit: type=1800 audit(1571902921.129:25): pid=7007 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 35.108059][ T26] audit: type=1800 audit(1571902921.139:26): pid=7007 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 35.132749][ T26] audit: type=1800 audit(1571902921.139:27): pid=7007 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 '10.128.0.236' (ECDSA) to the list of known hosts. 2019/10/24 07:42:08 fuzzer started 2019/10/24 07:42:09 dialing manager at 10.128.0.105:42135 2019/10/24 07:42:09 syscalls: 2524 2019/10/24 07:42:09 code coverage: enabled 2019/10/24 07:42:09 comparison tracing: enabled 2019/10/24 07:42:09 extra coverage: extra coverage is not supported by the kernel 2019/10/24 07:42:09 setuid sandbox: enabled 2019/10/24 07:42:09 namespace sandbox: enabled 2019/10/24 07:42:09 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/24 07:42:09 fault injection: enabled 2019/10/24 07:42:09 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/24 07:42:09 net packet injection: enabled 2019/10/24 07:42:09 net device setup: enabled 2019/10/24 07:42:09 concurrency sanitizer: enabled 2019/10/24 07:42:09 adding functions to KCSAN blacklist: 'tick_do_update_jiffies64' 'ep_poll' '__hrtimer_run_queues' 'tick_sched_do_timer' syzkaller login: [ 43.908744][ T7155] ================================================================== [ 43.916874][ T7155] BUG: KCSAN: data-race in __tcp_select_window / tcp_add_backlog [ 43.924570][ T7155] [ 43.927383][ T7155] write to 0xffff88812933e9ec of 4 bytes by interrupt on cpu 0: [ 43.934996][ T7155] tcp_add_backlog+0x4a0/0xcc0 [ 43.939742][ T7155] tcp_v4_rcv+0x1a60/0x1bb0 [ 43.944228][ T7155] ip_protocol_deliver_rcu+0x4d/0x420 [ 43.949579][ T7155] ip_local_deliver_finish+0x110/0x140 [ 43.955533][ T7155] ip_local_deliver+0x133/0x210 [ 43.961121][ T7155] ip_rcv_finish+0x121/0x160 [ 43.966214][ T7155] ip_rcv+0x18f/0x1a0 [ 43.970195][ T7155] __netif_receive_skb_one_core+0xa7/0xe0 [ 43.975899][ T7155] __netif_receive_skb+0x37/0xf0 [ 43.980819][ T7155] netif_receive_skb_internal+0x59/0x190 [ 43.986431][ T7155] napi_gro_receive+0x28f/0x330 [ 43.991300][ T7155] receive_buf+0x284/0x30b0 [ 43.996386][ T7155] virtnet_poll+0x436/0x7d0 [ 44.000866][ T7155] net_rx_action+0x3ae/0xa90 [ 44.005431][ T7155] [ 44.007741][ T7155] read to 0xffff88812933e9ec of 4 bytes by task 7155 on cpu 1: [ 44.015276][ T7155] __tcp_select_window+0x6b/0x4d0 [ 44.020475][ T7155] __tcp_ack_snd_check+0x117/0x4f0 [ 44.025581][ T7155] tcp_rcv_established+0xce9/0xf50 [ 44.030671][ T7155] tcp_v4_do_rcv+0x381/0x4e0 [ 44.035239][ T7155] __release_sock+0x135/0x1e0 [ 44.039891][ T7155] release_sock+0x61/0x160 [ 44.044305][ T7155] tcp_recvmsg+0x63b/0x1a30 [ 44.048787][ T7155] inet_recvmsg+0xbb/0x250 [ 44.053182][ T7155] sock_recvmsg+0x92/0xb0 [ 44.057503][ T7155] sock_read_iter+0x15f/0x1e0 [ 44.062160][ T7155] new_sync_read+0x389/0x4f0 [ 44.066729][ T7155] __vfs_read+0xb1/0xc0 [ 44.070862][ T7155] vfs_read+0x143/0x2c0 [ 44.075506][ T7155] [ 44.077819][ T7155] Reported by Kernel Concurrency Sanitizer on: [ 44.085533][ T7155] CPU: 1 PID: 7155 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 44.092979][ T7155] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.103166][ T7155] ================================================================== [ 44.111210][ T7155] Kernel panic - not syncing: panic_on_warn set ... [ 44.117782][ T7155] CPU: 1 PID: 7155 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 44.126164][ T7155] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.136193][ T7155] Call Trace: [ 44.139465][ T7155] dump_stack+0xf5/0x159 [ 44.143691][ T7155] panic+0x210/0x640 [ 44.147571][ T7155] ? sock_recvmsg+0x92/0xb0 [ 44.153019][ T7155] ? vprintk_func+0x8d/0x140 [ 44.157597][ T7155] kcsan_report.cold+0xc/0x10 [ 44.162266][ T7155] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 44.167807][ T7155] __tsan_read4+0x2c/0x30 [ 44.172113][ T7155] __tcp_select_window+0x6b/0x4d0 [ 44.177135][ T7155] __tcp_ack_snd_check+0x117/0x4f0 [ 44.182225][ T7155] tcp_rcv_established+0xce9/0xf50 [ 44.187342][ T7155] ? ipv4_dst_check+0xc6/0xf0 [ 44.192001][ T7155] tcp_v4_do_rcv+0x381/0x4e0 [ 44.196571][ T7155] __release_sock+0x135/0x1e0 [ 44.201226][ T7155] release_sock+0x61/0x160 [ 44.205640][ T7155] tcp_recvmsg+0x63b/0x1a30 [ 44.210151][ T7155] inet_recvmsg+0xbb/0x250 [ 44.214543][ T7155] ? __tsan_read8+0x2c/0x30 [ 44.219113][ T7155] ? inet_sendpage+0x100/0x100 [ 44.223855][ T7155] sock_recvmsg+0x92/0xb0 [ 44.228188][ T7155] sock_read_iter+0x15f/0x1e0 [ 44.232867][ T7155] new_sync_read+0x389/0x4f0 [ 44.237439][ T7155] __vfs_read+0xb1/0xc0 [ 44.241574][ T7155] vfs_read+0x143/0x2c0 [ 44.245713][ T7155] ksys_read+0xd5/0x1b0 [ 44.249848][ T7155] __x64_sys_read+0x4c/0x60 [ 44.254351][ T7155] do_syscall_64+0xcc/0x370 [ 44.259021][ T7155] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 44.264891][ T7155] RIP: 0033:0x47c530 [ 44.268769][ T7155] 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 [ 44.288524][ T7155] RSP: 002b:000000c4203147d8 EFLAGS: 00000212 ORIG_RAX: 0000000000000000 [ 44.296923][ T7155] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 44.304871][ T7155] RDX: 0000000000001000 RSI: 000000c42032e000 RDI: 0000000000000003 [ 44.312819][ T7155] RBP: 000000c420314830 R08: 0000000000000000 R09: 0000000000000000 [ 44.320767][ T7155] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000003 [ 44.329410][ T7155] R13: 000000c42007ebf0 R14: 0000000000000002 R15: ffffffffffffffff [ 44.338831][ T7155] Kernel Offset: disabled [ 44.343241][ T7155] Rebooting in 86400 seconds..