[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 34.718713][ T26] audit: type=1800 audit(1572279358.129:25): pid=7057 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 34.753668][ T26] audit: type=1800 audit(1572279358.139:26): pid=7057 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 34.781159][ T26] audit: type=1800 audit(1572279358.139:27): pid=7057 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 '10.128.0.8' (ECDSA) to the list of known hosts. 2019/10/28 16:16:09 fuzzer started 2019/10/28 16:16:11 dialing manager at 10.128.0.105:45117 2019/10/28 16:16:11 syscalls: 2540 2019/10/28 16:16:11 code coverage: enabled 2019/10/28 16:16:11 comparison tracing: enabled 2019/10/28 16:16:11 extra coverage: extra coverage is not supported by the kernel 2019/10/28 16:16:11 setuid sandbox: enabled 2019/10/28 16:16:11 namespace sandbox: enabled 2019/10/28 16:16:11 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/28 16:16:11 fault injection: enabled 2019/10/28 16:16:11 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/28 16:16:11 net packet injection: enabled 2019/10/28 16:16:11 net device setup: enabled 2019/10/28 16:16:11 concurrency sanitizer: enabled 2019/10/28 16:16:16 adding functions to KCSAN blacklist: 'ktime_get_real_seconds' 'ext4_free_inode' '__hrtimer_run_queues' 'tick_sched_do_timer' 'ep_poll' 'echo_char' 'task_dump_owner' 'do_syslog' 'do_nanosleep' 'pid_update_inode' 'rcu_gp_fqs_loop' '__tcp_select_window' 'tick_do_update_jiffies64' 'blk_mq_sched_dispatch_requests' '__nf_conntrack_find_get' 'tomoyo_supervisor' 'tcp_add_backlog' '__nf_ct_refresh_acct' 'find_next_bit' syzkaller login: [ 55.125597][ T7208] ================================================================== [ 55.133724][ T7208] BUG: KCSAN: data-race in tcp_poll / tcp_queue_rcv [ 55.140414][ T7208] [ 55.142734][ T7208] write to 0xffff8881226bee78 of 4 bytes by interrupt on cpu 0: [ 55.150356][ T7208] tcp_queue_rcv+0xe9/0x380 [ 55.154859][ T7208] tcp_rcv_established+0xbf1/0xf50 [ 55.159959][ T7208] tcp_v4_do_rcv+0x381/0x4e0 [ 55.164543][ T7208] tcp_v4_rcv+0x19dc/0x1bb0 [ 55.169035][ T7208] ip_protocol_deliver_rcu+0x4d/0x420 [ 55.174398][ T7208] ip_local_deliver_finish+0x110/0x140 [ 55.179852][ T7208] ip_local_deliver+0x133/0x210 [ 55.184694][ T7208] ip_rcv_finish+0x121/0x160 [ 55.189273][ T7208] ip_rcv+0x18f/0x1a0 [ 55.193252][ T7208] __netif_receive_skb_one_core+0xa7/0xe0 [ 55.198961][ T7208] __netif_receive_skb+0x37/0xf0 [ 55.203888][ T7208] netif_receive_skb_internal+0x59/0x190 [ 55.209502][ T7208] napi_gro_receive+0x28f/0x330 [ 55.214326][ T7208] receive_buf+0x284/0x30b0 [ 55.218797][ T7208] [ 55.221105][ T7208] read to 0xffff8881226bee78 of 4 bytes by task 7208 on cpu 1: [ 55.228620][ T7208] tcp_poll+0x204/0x6b0 [ 55.232753][ T7208] sock_poll+0xed/0x250 [ 55.236884][ T7208] ep_item_poll.isra.0+0x90/0x190 [ 55.241894][ T7208] ep_send_events_proc+0x113/0x590 [ 55.246983][ T7208] ep_scan_ready_list.constprop.0+0x189/0x500 [ 55.253022][ T7208] ep_poll+0xe3/0x900 [ 55.256975][ T7208] do_epoll_wait+0x162/0x180 [ 55.261552][ T7208] __x64_sys_epoll_pwait+0xcd/0x180 [ 55.266725][ T7208] do_syscall_64+0xcc/0x370 [ 55.271201][ T7208] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 55.277069][ T7208] [ 55.279371][ T7208] Reported by Kernel Concurrency Sanitizer on: [ 55.285496][ T7208] CPU: 1 PID: 7208 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 55.292954][ T7208] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.302980][ T7208] ================================================================== [ 55.311011][ T7208] Kernel panic - not syncing: panic_on_warn set ... [ 55.317571][ T7208] CPU: 1 PID: 7208 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 55.324997][ T7208] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.335035][ T7208] Call Trace: [ 55.338303][ T7208] dump_stack+0xf5/0x159 [ 55.342535][ T7208] panic+0x210/0x640 [ 55.346408][ T7208] ? do_syscall_64+0xcc/0x370 [ 55.351061][ T7208] ? vprintk_func+0x8d/0x140 [ 55.355626][ T7208] kcsan_report.cold+0xc/0x10 [ 55.360278][ T7208] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 55.365796][ T7208] __tsan_read4+0x2c/0x30 [ 55.370102][ T7208] tcp_poll+0x204/0x6b0 [ 55.374248][ T7208] ? tcp_alloc_md5sig_pool+0x320/0x320 [ 55.379681][ T7208] sock_poll+0xed/0x250 [ 55.383829][ T7208] ? sock_read_iter+0x1e0/0x1e0 [ 55.388659][ T7208] ep_item_poll.isra.0+0x90/0x190 [ 55.393661][ T7208] ep_send_events_proc+0x113/0x590 [ 55.398759][ T7208] ? __schedule+0x319/0x640 [ 55.403235][ T7208] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 55.408847][ T7208] ep_scan_ready_list.constprop.0+0x189/0x500 [ 55.414891][ T7208] ? ep_loop_check_proc+0x2f0/0x2f0 [ 55.420063][ T7208] ep_poll+0xe3/0x900 [ 55.424024][ T7208] ? wake_up_q+0x70/0x70 [ 55.428243][ T7208] do_epoll_wait+0x162/0x180 [ 55.432810][ T7208] __x64_sys_epoll_pwait+0xcd/0x180 [ 55.438015][ T7208] do_syscall_64+0xcc/0x370 [ 55.442493][ T7208] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 55.448361][ T7208] RIP: 0033:0x45b300 [ 55.452233][ T7208] Code: 0f 05 89 44 24 20 c3 cc cc cc 8b 7c 24 08 48 8b 74 24 10 8b 54 24 18 44 8b 54 24 1c 49 c7 c0 00 00 00 00 b8 19 01 00 00 0f 05 <89> 44 24 20 c3 cc cc cc cc cc cc cc cc cc cc cc 8b 7c 24 08 48 c7 [ 55.471852][ T7208] RSP: 002b:000000c42004d860 EFLAGS: 00000246 ORIG_RAX: 0000000000000119 [ 55.480238][ T7208] RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 000000000045b300 [ 55.488183][ T7208] RDX: 0000000000000080 RSI: 000000c42004d8a0 RDI: 0000000000000004 [ 55.496128][ T7208] RBP: 000000c42004dea0 R08: 0000000000000000 R09: 0000000000000000 [ 55.504070][ T7208] R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000010 [ 55.512016][ T7208] R13: ffffffffffffffff R14: 0000000000000004 R15: ffffffffffffffff [ 55.521231][ T7208] Kernel Offset: disabled [ 55.525567][ T7208] Rebooting in 86400 seconds..