[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 35.681091][ T25] audit: type=1800 audit(1572003345.470:25): pid=7085 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 35.732968][ T25] audit: type=1800 audit(1572003345.470:26): pid=7085 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 35.752952][ T25] audit: type=1800 audit(1572003345.470:27): pid=7085 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 '10.128.0.192' (ECDSA) to the list of known hosts. 2019/10/25 11:35:55 fuzzer started 2019/10/25 11:35:56 dialing manager at 10.128.0.105:33971 2019/10/25 11:35:56 syscalls: 2529 2019/10/25 11:35:56 code coverage: enabled 2019/10/25 11:35:56 comparison tracing: enabled 2019/10/25 11:35:56 extra coverage: extra coverage is not supported by the kernel 2019/10/25 11:35:56 setuid sandbox: enabled 2019/10/25 11:35:56 namespace sandbox: enabled 2019/10/25 11:35:56 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/25 11:35:56 fault injection: enabled 2019/10/25 11:35:56 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/25 11:35:56 net packet injection: enabled 2019/10/25 11:35:56 net device setup: enabled 2019/10/25 11:35:56 concurrency sanitizer: enabled 2019/10/25 11:35:57 adding functions to KCSAN blacklist: '__hrtimer_run_queues' 'generic_permission' 'find_next_bit' 'tomoyo_supervisor' 'run_timer_softirq' 'ext4_free_inodes_count' syzkaller login: [ 48.326836][ T7240] ================================================================== [ 48.334977][ T7240] BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg [ 48.342153][ T7240] [ 48.344469][ T7240] write to 0xffff888126b9e138 of 8 bytes by interrupt on cpu 0: [ 48.352376][ T7240] tcp_add_backlog+0x45a/0xcc0 [ 48.357136][ T7240] tcp_v4_rcv+0x1a60/0x1bb0 [ 48.361771][ T7240] ip_protocol_deliver_rcu+0x4d/0x420 [ 48.367264][ T7240] ip_local_deliver_finish+0x110/0x140 [ 48.372761][ T7240] ip_local_deliver+0x133/0x210 [ 48.377645][ T7240] ip_rcv_finish+0x121/0x160 [ 48.382217][ T7240] ip_rcv+0x18f/0x1a0 [ 48.386180][ T7240] __netif_receive_skb_one_core+0xa7/0xe0 [ 48.391893][ T7240] __netif_receive_skb+0x37/0xf0 [ 48.396807][ T7240] netif_receive_skb_internal+0x59/0x190 [ 48.402413][ T7240] napi_gro_receive+0x28f/0x330 [ 48.407673][ T7240] receive_buf+0x284/0x30b0 [ 48.412413][ T7240] virtnet_poll+0x436/0x7d0 [ 48.416981][ T7240] net_rx_action+0x3ae/0xa90 [ 48.421541][ T7240] [ 48.423850][ T7240] read to 0xffff888126b9e138 of 8 bytes by task 7240 on cpu 1: [ 48.431370][ T7240] tcp_recvmsg+0x470/0x1a30 [ 48.435849][ T7240] inet_recvmsg+0xbb/0x250 [ 48.440851][ T7240] sock_recvmsg+0x92/0xb0 [ 48.445163][ T7240] sock_read_iter+0x15f/0x1e0 [ 48.449837][ T7240] new_sync_read+0x389/0x4f0 [ 48.454420][ T7240] __vfs_read+0xb1/0xc0 [ 48.458657][ T7240] vfs_read+0x143/0x2c0 [ 48.462806][ T7240] ksys_read+0xd5/0x1b0 [ 48.466939][ T7240] __x64_sys_read+0x4c/0x60 [ 48.471432][ T7240] do_syscall_64+0xcc/0x370 [ 48.475946][ T7240] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 48.481809][ T7240] [ 48.484124][ T7240] Reported by Kernel Concurrency Sanitizer on: [ 48.490445][ T7240] CPU: 1 PID: 7240 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 48.497945][ T7240] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.508256][ T7240] ================================================================== [ 48.516318][ T7240] Kernel panic - not syncing: panic_on_warn set ... [ 48.522997][ T7240] CPU: 1 PID: 7240 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 48.530446][ T7240] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.540592][ T7240] Call Trace: [ 48.543923][ T7240] dump_stack+0xf5/0x159 [ 48.548150][ T7240] panic+0x210/0x640 [ 48.552033][ T7240] ? __x64_sys_read+0x4c/0x60 [ 48.556693][ T7240] ? vprintk_func+0x8d/0x140 [ 48.561379][ T7240] kcsan_report.cold+0xc/0x10 [ 48.566037][ T7240] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 48.571575][ T7240] __tsan_read8+0x2c/0x30 [ 48.575886][ T7240] tcp_recvmsg+0x470/0x1a30 [ 48.580379][ T7240] inet_recvmsg+0xbb/0x250 [ 48.584958][ T7240] ? __tsan_read8+0x2c/0x30 [ 48.589441][ T7240] ? inet_sendpage+0x100/0x100 [ 48.594316][ T7240] sock_recvmsg+0x92/0xb0 [ 48.598659][ T7240] sock_read_iter+0x15f/0x1e0 [ 48.603453][ T7240] new_sync_read+0x389/0x4f0 [ 48.608033][ T7240] __vfs_read+0xb1/0xc0 [ 48.612171][ T7240] vfs_read+0x143/0x2c0 [ 48.616321][ T7240] ksys_read+0xd5/0x1b0 [ 48.620457][ T7240] __x64_sys_read+0x4c/0x60 [ 48.624954][ T7240] do_syscall_64+0xcc/0x370 [ 48.629441][ T7240] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 48.635315][ T7240] RIP: 0033:0x47c530 [ 48.639204][ T7240] 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 [ 48.658873][ T7240] RSP: 002b:000000c4203037d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 [ 48.667263][ T7240] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 48.675490][ T7240] RDX: 0000000000001000 RSI: 000000c42038a000 RDI: 0000000000000003 [ 48.683607][ T7240] RBP: 000000c420303828 R08: 0000000000000000 R09: 0000000000000000 [ 48.691653][ T7240] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004 [ 48.699629][ T7240] R13: ffffffffffffffff R14: 0000000000000004 R15: ffffffffffffffff [ 48.709272][ T7240] Kernel Offset: disabled [ 48.713595][ T7240] Rebooting in 86400 seconds..