[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 32.943378][ T25] audit: type=1800 audit(1571780942.020:25): pid=7038 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 32.969358][ T25] audit: type=1800 audit(1571780942.020:26): pid=7038 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 32.989567][ T25] audit: type=1800 audit(1571780942.020:27): pid=7038 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 '10.128.10.58' (ECDSA) to the list of known hosts. 2019/10/22 21:49:08 fuzzer started 2019/10/22 21:49:10 dialing manager at 10.128.0.105:33369 2019/10/22 21:49:10 syscalls: 2524 2019/10/22 21:49:10 code coverage: enabled 2019/10/22 21:49:10 comparison tracing: enabled 2019/10/22 21:49:10 extra coverage: extra coverage is not supported by the kernel syzkaller login: [ 41.171448][ T7187] ================================================================== [ 41.179675][ T7187] BUG: KCSAN: data-race in tcp_ack / tcp_poll [ 41.185769][ T7187] [ 41.188079][ T7187] write to 0xffff88812650d348 of 4 bytes by interrupt on cpu 0: [ 41.195685][ T7187] tcp_ack+0xf2c/0x3170 [ 41.199835][ T7187] tcp_rcv_established+0x37e/0xf50 [ 41.204923][ T7187] tcp_v4_do_rcv+0x381/0x4e0 [ 41.209504][ T7187] tcp_v4_rcv+0x19dc/0x1bb0 [ 41.213982][ T7187] ip_protocol_deliver_rcu+0x4d/0x420 [ 41.219342][ T7187] ip_local_deliver_finish+0x110/0x140 [ 41.224774][ T7187] ip_local_deliver+0x133/0x210 [ 41.229598][ T7187] ip_rcv_finish+0x121/0x160 [ 41.234209][ T7187] ip_rcv+0x18f/0x1a0 [ 41.238171][ T7187] __netif_receive_skb_one_core+0xa7/0xe0 [ 41.243867][ T7187] __netif_receive_skb+0x37/0xf0 [ 41.248784][ T7187] netif_receive_skb_internal+0x59/0x190 [ 41.254396][ T7187] napi_gro_receive+0x28f/0x330 [ 41.259331][ T7187] receive_buf+0x284/0x30b0 [ 41.263806][ T7187] [ 41.266120][ T7187] read to 0xffff88812650d348 of 4 bytes by task 7187 on cpu 1: [ 41.273645][ T7187] tcp_poll+0x422/0x6b0 [ 41.277783][ T7187] sock_poll+0xed/0x250 [ 41.281920][ T7187] do_select+0x7d0/0x1020 [ 41.286226][ T7187] core_sys_select+0x381/0x550 [ 41.290965][ T7187] kern_select+0x106/0x170 [ 41.295361][ T7187] __x64_sys_select+0x70/0x90 [ 41.300172][ T7187] do_syscall_64+0xcc/0x370 [ 41.304671][ T7187] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 41.310535][ T7187] [ 41.312839][ T7187] Reported by Kernel Concurrency Sanitizer on: [ 41.318971][ T7187] CPU: 1 PID: 7187 Comm: sshd Not tainted 5.4.0-rc3+ #0 [ 41.325887][ T7187] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.335926][ T7187] ================================================================== [ 41.343961][ T7187] Kernel panic - not syncing: panic_on_warn set ... [ 41.350525][ T7187] CPU: 1 PID: 7187 Comm: sshd Not tainted 5.4.0-rc3+ #0 [ 41.357452][ T7187] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.367495][ T7187] Call Trace: [ 41.370769][ T7187] dump_stack+0xf5/0x159 [ 41.374991][ T7187] panic+0x210/0x640 [ 41.378882][ T7187] ? vprintk_func+0x8d/0x140 [ 41.383471][ T7187] kcsan_report.cold+0xc/0x10 [ 41.388127][ T7187] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 41.393663][ T7187] __tsan_read4+0x2c/0x30 [ 41.397990][ T7187] tcp_poll+0x422/0x6b0 [ 41.402134][ T7187] ? tcp_alloc_md5sig_pool+0x320/0x320 [ 41.407578][ T7187] sock_poll+0xed/0x250 [ 41.411762][ T7187] ? sock_read_iter+0x1e0/0x1e0 [ 41.416693][ T7187] do_select+0x7d0/0x1020 [ 41.421031][ T7187] ? poll_initwait+0xa0/0xa0 [ 41.425607][ T7187] ? poll_select_finish+0x440/0x440 [ 41.430790][ T7187] ? poll_select_finish+0x440/0x440 [ 41.435980][ T7187] ? poll_select_finish+0x440/0x440 [ 41.441156][ T7187] ? poll_select_finish+0x440/0x440 [ 41.446344][ T7187] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 41.451950][ T7187] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 41.457573][ T7187] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 41.463442][ T7187] ? __tsan_read8+0x2c/0x30 [ 41.467921][ T7187] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 41.474138][ T7187] ? timestamp_truncate+0x11b/0x160 [ 41.479325][ T7187] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 41.484941][ T7187] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 41.490597][ T7187] ? __tsan_read8+0x2c/0x30 [ 41.495107][ T7187] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 41.500722][ T7187] ? check_stack_object+0xda/0x110 [ 41.505813][ T7187] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 41.511591][ T7187] ? __tsan_read8+0x2c/0x30 [ 41.516081][ T7187] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 41.522357][ T7187] core_sys_select+0x381/0x550 [ 41.527108][ T7187] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 41.532731][ T7187] ? __tsan_read8+0x2c/0x30 [ 41.537224][ T7187] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 41.543093][ T7187] ? __tsan_write8+0x32/0x40 [ 41.547660][ T7187] ? ktime_get_ts64+0x286/0x2c0 [ 41.552489][ T7187] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 41.558183][ T7187] ? timespec64_add_safe+0xae/0xd0 [ 41.563277][ T7187] kern_select+0x106/0x170 [ 41.567689][ T7187] __x64_sys_select+0x70/0x90 [ 41.572359][ T7187] do_syscall_64+0xcc/0x370 [ 41.576841][ T7187] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 41.582707][ T7187] RIP: 0033:0x7f2a4d4d2dd3 [ 41.587103][ T7187] Code: 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 90 90 90 83 3d 25 48 2b 00 00 75 13 49 89 ca b8 17 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 ab 2f 01 00 48 89 04 24 [ 41.606680][ T7187] RSP: 002b:00007ffcc6b7d918 EFLAGS: 00000246 ORIG_RAX: 0000000000000017 [ 41.615066][ T7187] RAX: ffffffffffffffda RBX: 00007ffcc6b7d9a0 RCX: 00007f2a4d4d2dd3 [ 41.623013][ T7187] RDX: 0000557255ba5af0 RSI: 0000557255ba5b10 RDI: 000000000000000c [ 41.630960][ T7187] RBP: 00005572550cf8dc R08: 00007ffcc6b7d940 R09: 0101010101010101 [ 41.638921][ T7187] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcc6b7d9a8 [ 41.646889][ T7187] R13: 0000000000000000 R14: 00007ffcc6b7d998 R15: 00007ffcc6b7d99c [ 41.656210][ T7187] Kernel Offset: disabled [ 41.660542][ T7187] Rebooting in 86400 seconds..