[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 34.447531][ T26] audit: type=1800 audit(1571759169.599:25): pid=7059 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 34.474563][ T26] audit: type=1800 audit(1571759169.609:26): pid=7059 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 34.501241][ T26] audit: type=1800 audit(1571759169.609:27): pid=7059 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 '10.128.0.52' (ECDSA) to the list of known hosts. 2019/10/22 15:46:17 fuzzer started 2019/10/22 15:46:19 dialing manager at 10.128.0.105:33369 2019/10/22 15:46:19 syscalls: 2524 2019/10/22 15:46:19 code coverage: enabled 2019/10/22 15:46:19 comparison tracing: enabled 2019/10/22 15:46:19 extra coverage: extra coverage is not supported by the kernel 2019/10/22 15:46:19 setuid sandbox: enabled 2019/10/22 15:46:19 namespace sandbox: enabled 2019/10/22 15:46:19 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/22 15:46:19 fault injection: enabled 2019/10/22 15:46:19 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/22 15:46:19 net packet injection: enabled 2019/10/22 15:46:19 net device setup: enabled 2019/10/22 15:46:19 concurrency sanitizer: enabled syzkaller login: [ 45.129795][ T7211] ================================================================== [ 45.137920][ T7211] BUG: KCSAN: data-race in __tcp_select_window / tcp_add_backlog [ 45.145617][ T7211] [ 45.147945][ T7211] write to 0xffff888122e529ec of 4 bytes by interrupt on cpu 0: [ 45.155563][ T7211] tcp_add_backlog+0x4a0/0xcc0 [ 45.160339][ T7211] tcp_v4_rcv+0x1a60/0x1bb0 [ 45.164820][ T7211] ip_protocol_deliver_rcu+0x4d/0x420 [ 45.170164][ T7211] ip_local_deliver_finish+0x110/0x140 [ 45.175638][ T7211] ip_local_deliver+0x133/0x210 [ 45.180461][ T7211] ip_rcv_finish+0x121/0x160 [ 45.185063][ T7211] ip_rcv+0x18f/0x1a0 [ 45.189029][ T7211] __netif_receive_skb_one_core+0xa7/0xe0 [ 45.194723][ T7211] __netif_receive_skb+0x37/0xf0 [ 45.199635][ T7211] netif_receive_skb_internal+0x59/0x190 [ 45.205244][ T7211] napi_gro_receive+0x28f/0x330 [ 45.210067][ T7211] receive_buf+0x284/0x30b0 [ 45.214545][ T7211] virtnet_poll+0x436/0x7d0 [ 45.219025][ T7211] net_rx_action+0x3ae/0xa90 [ 45.223582][ T7211] [ 45.225957][ T7211] read to 0xffff888122e529ec of 4 bytes by task 7211 on cpu 1: [ 45.233491][ T7211] __tcp_select_window+0x6b/0x4d0 [ 45.238534][ T7211] __tcp_transmit_skb+0x700/0x1d60 [ 45.243623][ T7211] __tcp_send_ack+0x246/0x300 [ 45.248276][ T7211] tcp_send_ack+0x34/0x40 [ 45.252580][ T7211] tcp_cleanup_rbuf+0x130/0x360 [ 45.257403][ T7211] tcp_recvmsg+0x633/0x1a30 [ 45.261882][ T7211] inet_recvmsg+0xbb/0x250 [ 45.266272][ T7211] sock_recvmsg+0x92/0xb0 [ 45.270575][ T7211] sock_read_iter+0x15f/0x1e0 [ 45.275222][ T7211] new_sync_read+0x389/0x4f0 [ 45.279787][ T7211] __vfs_read+0xb1/0xc0 [ 45.283915][ T7211] vfs_read+0x143/0x2c0 [ 45.288086][ T7211] ksys_read+0xd5/0x1b0 [ 45.292209][ T7211] [ 45.294510][ T7211] Reported by Kernel Concurrency Sanitizer on: [ 45.300639][ T7211] CPU: 1 PID: 7211 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 45.308061][ T7211] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.318089][ T7211] ================================================================== [ 45.326124][ T7211] Kernel panic - not syncing: panic_on_warn set ... [ 45.332687][ T7211] CPU: 1 PID: 7211 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 45.340155][ T7211] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.350191][ T7211] Call Trace: [ 45.353478][ T7211] dump_stack+0xf5/0x159 [ 45.357698][ T7211] panic+0x210/0x640 [ 45.361574][ T7211] ? sock_read_iter+0x15f/0x1e0 [ 45.366402][ T7211] ? vprintk_func+0x8d/0x140 [ 45.370970][ T7211] kcsan_report.cold+0xc/0x10 [ 45.375635][ T7211] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 45.381155][ T7211] __tsan_read4+0x2c/0x30 [ 45.385460][ T7211] __tcp_select_window+0x6b/0x4d0 [ 45.390470][ T7211] __tcp_transmit_skb+0x700/0x1d60 [ 45.395564][ T7211] __tcp_send_ack+0x246/0x300 [ 45.400222][ T7211] tcp_send_ack+0x34/0x40 [ 45.404529][ T7211] tcp_cleanup_rbuf+0x130/0x360 [ 45.409356][ T7211] tcp_recvmsg+0x633/0x1a30 [ 45.413843][ T7211] inet_recvmsg+0xbb/0x250 [ 45.418237][ T7211] ? __tsan_read8+0x2c/0x30 [ 45.422730][ T7211] ? inet_sendpage+0x100/0x100 [ 45.427470][ T7211] sock_recvmsg+0x92/0xb0 [ 45.431776][ T7211] sock_read_iter+0x15f/0x1e0 [ 45.436438][ T7211] new_sync_read+0x389/0x4f0 [ 45.441019][ T7211] __vfs_read+0xb1/0xc0 [ 45.445151][ T7211] vfs_read+0x143/0x2c0 [ 45.449282][ T7211] ksys_read+0xd5/0x1b0 [ 45.453413][ T7211] __x64_sys_read+0x4c/0x60 [ 45.457900][ T7211] do_syscall_64+0xcc/0x370 [ 45.462388][ T7211] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 45.468250][ T7211] RIP: 0033:0x47c530 [ 45.472120][ T7211] 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 [ 45.491698][ T7211] RSP: 002b:000000c4204f77d8 EFLAGS: 00000212 ORIG_RAX: 0000000000000000 [ 45.500086][ T7211] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 45.508034][ T7211] RDX: 0000000000001000 RSI: 000000c4201be000 RDI: 0000000000000003 [ 45.515979][ T7211] RBP: 000000c4204f7830 R08: 0000000000000000 R09: 0000000000000000 [ 45.523923][ T7211] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000008 [ 45.531866][ T7211] R13: ffffffffffffffff R14: 0000000000000002 R15: ffffffffffffffff [ 45.541087][ T7211] Kernel Offset: disabled [ 45.545403][ T7211] Rebooting in 86400 seconds..