[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 34.387448][ T23] audit: type=1800 audit(1571784412.193:25): pid=7050 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 34.414811][ T23] audit: type=1800 audit(1571784412.193:26): pid=7050 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 34.441628][ T23] audit: type=1800 audit(1571784412.193:27): pid=7050 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 '10.128.0.173' (ECDSA) to the list of known hosts. 2019/10/22 22:47:03 fuzzer started 2019/10/22 22:47:04 dialing manager at 10.128.0.105:33369 2019/10/22 22:47:05 syscalls: 2524 2019/10/22 22:47:05 code coverage: enabled 2019/10/22 22:47:05 comparison tracing: enabled 2019/10/22 22:47:05 extra coverage: extra coverage is not supported by the kernel 2019/10/22 22:47:05 setuid sandbox: enabled 2019/10/22 22:47:05 namespace sandbox: enabled 2019/10/22 22:47:05 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/22 22:47:05 fault injection: enabled 2019/10/22 22:47:05 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/22 22:47:05 net packet injection: enabled 2019/10/22 22:47:05 net device setup: enabled 2019/10/22 22:47:05 concurrency sanitizer: enabled syzkaller login: [ 47.505643][ T7200] ================================================================== [ 47.513758][ T7200] BUG: KCSAN: data-race in __tcp_select_window / tcp_add_backlog [ 47.521658][ T7200] [ 47.523998][ T7200] write to 0xffff8881257ab2ec of 4 bytes by interrupt on cpu 0: [ 47.531794][ T7200] tcp_add_backlog+0x4a0/0xcc0 [ 47.536537][ T7200] tcp_v4_rcv+0x1a60/0x1bb0 [ 47.541033][ T7200] ip_protocol_deliver_rcu+0x4d/0x420 [ 47.546382][ T7200] ip_local_deliver_finish+0x110/0x140 [ 47.552771][ T7200] ip_local_deliver+0x133/0x210 [ 47.557595][ T7200] ip_rcv_finish+0x121/0x160 [ 47.562159][ T7200] ip_rcv+0x18f/0x1a0 [ 47.566134][ T7200] __netif_receive_skb_one_core+0xa7/0xe0 [ 47.571831][ T7200] __netif_receive_skb+0x37/0xf0 [ 47.576744][ T7200] netif_receive_skb_internal+0x59/0x190 [ 47.582367][ T7200] napi_gro_receive+0x28f/0x330 [ 47.587209][ T7200] receive_buf+0x284/0x30b0 [ 47.591693][ T7200] virtnet_poll+0x436/0x7d0 [ 47.596173][ T7200] net_rx_action+0x3ae/0xa90 [ 47.600734][ T7200] [ 47.603048][ T7200] read to 0xffff8881257ab2ec of 4 bytes by task 7200 on cpu 1: [ 47.610576][ T7200] __tcp_select_window+0x6b/0x4d0 [ 47.615589][ T7200] __tcp_transmit_skb+0x700/0x1d60 [ 47.620678][ T7200] __tcp_send_ack+0x246/0x300 [ 47.625331][ T7200] tcp_send_ack+0x34/0x40 [ 47.629648][ T7200] tcp_cleanup_rbuf+0x130/0x360 [ 47.634476][ T7200] tcp_recvmsg+0x633/0x1a30 [ 47.638957][ T7200] inet_recvmsg+0xbb/0x250 [ 47.643351][ T7200] sock_recvmsg+0x92/0xb0 [ 47.647662][ T7200] sock_read_iter+0x15f/0x1e0 [ 47.652316][ T7200] new_sync_read+0x389/0x4f0 [ 47.656893][ T7200] __vfs_read+0xb1/0xc0 [ 47.661023][ T7200] vfs_read+0x143/0x2c0 [ 47.665158][ T7200] ksys_read+0xd5/0x1b0 [ 47.669286][ T7200] [ 47.671612][ T7200] Reported by Kernel Concurrency Sanitizer on: [ 47.677742][ T7200] CPU: 1 PID: 7200 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 47.685170][ T7200] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.695215][ T7200] ================================================================== [ 47.703250][ T7200] Kernel panic - not syncing: panic_on_warn set ... [ 47.709825][ T7200] CPU: 1 PID: 7200 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 47.717264][ T7200] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.727317][ T7200] Call Trace: [ 47.730592][ T7200] dump_stack+0xf5/0x159 [ 47.734824][ T7200] panic+0x210/0x640 [ 47.738698][ T7200] ? sock_read_iter+0x15f/0x1e0 [ 47.743527][ T7200] ? vprintk_func+0x8d/0x140 [ 47.748112][ T7200] kcsan_report.cold+0xc/0x10 [ 47.752768][ T7200] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 47.758297][ T7200] __tsan_read4+0x2c/0x30 [ 47.762606][ T7200] __tcp_select_window+0x6b/0x4d0 [ 47.767609][ T7200] __tcp_transmit_skb+0x700/0x1d60 [ 47.772707][ T7200] __tcp_send_ack+0x246/0x300 [ 47.777380][ T7200] tcp_send_ack+0x34/0x40 [ 47.781704][ T7200] tcp_cleanup_rbuf+0x130/0x360 [ 47.787056][ T7200] tcp_recvmsg+0x633/0x1a30 [ 47.791544][ T7200] inet_recvmsg+0xbb/0x250 [ 47.795942][ T7200] ? __tsan_read8+0x2c/0x30 [ 47.800437][ T7200] ? inet_sendpage+0x100/0x100 [ 47.805181][ T7200] sock_recvmsg+0x92/0xb0 [ 47.809490][ T7200] sock_read_iter+0x15f/0x1e0 [ 47.814148][ T7200] new_sync_read+0x389/0x4f0 [ 47.818722][ T7200] __vfs_read+0xb1/0xc0 [ 47.822858][ T7200] vfs_read+0x143/0x2c0 [ 47.827004][ T7200] ksys_read+0xd5/0x1b0 [ 47.831140][ T7200] __x64_sys_read+0x4c/0x60 [ 47.835623][ T7200] do_syscall_64+0xcc/0x370 [ 47.840105][ T7200] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 47.845974][ T7200] RIP: 0033:0x47c530 [ 47.849939][ T7200] 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 [ 47.869522][ T7200] RSP: 002b:000000c4204fb810 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 [ 47.877928][ T7200] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 47.885891][ T7200] RDX: 0000000000001000 RSI: 000000c4203c8000 RDI: 0000000000000003 [ 47.894035][ T7200] RBP: 000000c4204fb868 R08: 0000000000000000 R09: 0000000000000000 [ 47.901989][ T7200] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 [ 47.909981][ T7200] R13: 000000c42007f768 R14: 0000000000000002 R15: ffffffffffffffff [ 47.919368][ T7200] Kernel Offset: disabled [ 47.923688][ T7200] Rebooting in 86400 seconds..