[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 36.064624][ T23] audit: type=1800 audit(1572728686.423:25): pid=7106 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 36.084398][ T23] audit: type=1800 audit(1572728686.423:26): pid=7106 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 36.112452][ T23] audit: type=1800 audit(1572728686.423:27): pid=7106 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 '10.128.0.9' (ECDSA) to the list of known hosts. 2019/11/02 21:04:54 fuzzer started 2019/11/02 21:04:56 dialing manager at 10.128.0.105:46001 2019/11/02 21:04:56 syscalls: 2554 2019/11/02 21:04:56 code coverage: enabled 2019/11/02 21:04:56 comparison tracing: enabled 2019/11/02 21:04:56 extra coverage: extra coverage is not supported by the kernel 2019/11/02 21:04:56 setuid sandbox: enabled 2019/11/02 21:04:56 namespace sandbox: enabled 2019/11/02 21:04:56 Android sandbox: /sys/fs/selinux/policy does not exist 2019/11/02 21:04:56 fault injection: enabled 2019/11/02 21:04:56 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/11/02 21:04:56 net packet injection: enabled 2019/11/02 21:04:56 net device setup: enabled 2019/11/02 21:04:56 concurrency sanitizer: enabled 2019/11/02 21:04:57 adding functions to KCSAN blacklist: '__nf_conntrack_find_get' 'find_next_bit' 'vm_area_dup' 'task_dump_owner' 'pcpu_alloc' '__hrtimer_run_queues' 'rcu_gp_fqs_check_wake' syzkaller login: [ 47.552261][ T7260] ================================================================== [ 47.560417][ T7260] BUG: KCSAN: data-race in __tcp_select_window / tcp_add_backlog [ 47.568107][ T7260] [ 47.570427][ T7260] write to 0xffff888122f752ec of 4 bytes by interrupt on cpu 0: [ 47.578035][ T7260] tcp_add_backlog+0x4a0/0xcc0 [ 47.582777][ T7260] tcp_v4_rcv+0x1a60/0x1bb0 [ 47.587256][ T7260] ip_protocol_deliver_rcu+0x4d/0x420 [ 47.592602][ T7260] ip_local_deliver_finish+0x110/0x140 [ 47.598049][ T7260] ip_local_deliver+0x133/0x210 [ 47.602877][ T7260] ip_rcv_finish+0x121/0x160 [ 47.607457][ T7260] ip_rcv+0x18f/0x1a0 [ 47.611430][ T7260] __netif_receive_skb_one_core+0xa7/0xe0 [ 47.617125][ T7260] __netif_receive_skb+0x37/0xf0 [ 47.622039][ T7260] netif_receive_skb_internal+0x59/0x190 [ 47.627648][ T7260] napi_gro_receive+0x28f/0x330 [ 47.632488][ T7260] receive_buf+0x284/0x30b0 [ 47.636974][ T7260] virtnet_poll+0x436/0x7d0 [ 47.641474][ T7260] net_rx_action+0x3ae/0xa90 [ 47.646032][ T7260] [ 47.648338][ T7260] read to 0xffff888122f752ec of 4 bytes by task 7260 on cpu 1: [ 47.655856][ T7260] __tcp_select_window+0x6b/0x4d0 [ 47.660856][ T7260] __tcp_transmit_skb+0x700/0x1d60 [ 47.665943][ T7260] __tcp_send_ack+0x246/0x300 [ 47.670598][ T7260] tcp_send_ack+0x34/0x40 [ 47.674902][ T7260] tcp_cleanup_rbuf+0x130/0x360 [ 47.679729][ T7260] tcp_recvmsg+0x633/0x1a30 [ 47.684224][ T7260] inet_recvmsg+0xbb/0x250 [ 47.688628][ T7260] sock_recvmsg+0x92/0xb0 [ 47.692943][ T7260] sock_read_iter+0x15f/0x1e0 [ 47.697603][ T7260] new_sync_read+0x389/0x4f0 [ 47.702190][ T7260] __vfs_read+0xb1/0xc0 [ 47.706330][ T7260] vfs_read+0x143/0x2c0 [ 47.710458][ T7260] ksys_read+0xd5/0x1b0 [ 47.714591][ T7260] [ 47.716890][ T7260] Reported by Kernel Concurrency Sanitizer on: [ 47.723031][ T7260] CPU: 1 PID: 7260 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 47.730454][ T7260] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.740493][ T7260] ================================================================== [ 47.748528][ T7260] Kernel panic - not syncing: panic_on_warn set ... [ 47.755101][ T7260] CPU: 1 PID: 7260 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 47.762536][ T7260] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.772564][ T7260] Call Trace: [ 47.775838][ T7260] dump_stack+0xf5/0x159 [ 47.780059][ T7260] panic+0x210/0x640 [ 47.783945][ T7260] ? sock_read_iter+0x15f/0x1e0 [ 47.788781][ T7260] ? vprintk_func+0x8d/0x140 [ 47.793353][ T7260] kcsan_report.cold+0xc/0x10 [ 47.798011][ T7260] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 47.803595][ T7260] __tsan_read4+0x2c/0x30 [ 47.807928][ T7260] __tcp_select_window+0x6b/0x4d0 [ 47.812963][ T7260] __tcp_transmit_skb+0x700/0x1d60 [ 47.818062][ T7260] __tcp_send_ack+0x246/0x300 [ 47.822726][ T7260] tcp_send_ack+0x34/0x40 [ 47.827032][ T7260] tcp_cleanup_rbuf+0x130/0x360 [ 47.831869][ T7260] tcp_recvmsg+0x633/0x1a30 [ 47.836371][ T7260] inet_recvmsg+0xbb/0x250 [ 47.840765][ T7260] ? __tsan_read8+0x2c/0x30 [ 47.845250][ T7260] ? inet_sendpage+0x100/0x100 [ 47.850185][ T7260] sock_recvmsg+0x92/0xb0 [ 47.854502][ T7260] sock_read_iter+0x15f/0x1e0 [ 47.859164][ T7260] new_sync_read+0x389/0x4f0 [ 47.863735][ T7260] __vfs_read+0xb1/0xc0 [ 47.867867][ T7260] vfs_read+0x143/0x2c0 [ 47.872001][ T7260] ksys_read+0xd5/0x1b0 [ 47.876144][ T7260] __x64_sys_read+0x4c/0x60 [ 47.880629][ T7260] do_syscall_64+0xcc/0x370 [ 47.886686][ T7260] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 47.892566][ T7260] RIP: 0033:0x47c530 [ 47.896449][ T7260] 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 [ 47.916040][ T7260] RSP: 002b:000000c4204eb7d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 [ 47.924451][ T7260] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 47.932399][ T7260] RDX: 0000000000001000 RSI: 000000c420058000 RDI: 0000000000000003 [ 47.940365][ T7260] RBP: 000000c4204eb828 R08: 0000000000000000 R09: 0000000000000000 [ 47.948328][ T7260] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008 [ 47.956275][ T7260] R13: ffffffffffffffff R14: 0000000000000002 R15: ffffffffffffffff [ 47.965745][ T7260] Kernel Offset: disabled [ 47.970080][ T7260] Rebooting in 86400 seconds..