[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 35.806923][ T26] audit: type=1800 audit(1572003352.815:25): pid=7095 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 35.843571][ T26] audit: type=1800 audit(1572003352.815:26): pid=7095 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 35.864542][ T26] audit: type=1800 audit(1572003352.815:27): pid=7095 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 '10.128.0.73' (ECDSA) to the list of known hosts. 2019/10/25 11:36:00 fuzzer started 2019/10/25 11:36:01 dialing manager at 10.128.0.105:33971 2019/10/25 11:36:01 syscalls: 2529 2019/10/25 11:36:01 code coverage: enabled 2019/10/25 11:36:01 comparison tracing: enabled 2019/10/25 11:36:01 extra coverage: extra coverage is not supported by the kernel 2019/10/25 11:36:01 setuid sandbox: enabled 2019/10/25 11:36:01 namespace sandbox: enabled 2019/10/25 11:36:01 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/25 11:36:01 fault injection: enabled 2019/10/25 11:36:01 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/25 11:36:01 net packet injection: enabled 2019/10/25 11:36:01 net device setup: enabled 2019/10/25 11:36:01 concurrency sanitizer: enabled 2019/10/25 11:36:01 adding functions to KCSAN blacklist: 'find_next_bit' 'tomoyo_supervisor' 'run_timer_softirq' 'ext4_free_inodes_count' '__hrtimer_run_queues' 'generic_permission' syzkaller login: [ 45.077262][ T7254] ================================================================== [ 45.085522][ T7254] BUG: KCSAN: data-race in tcp_add_backlog / tcp_grow_window.isra.0 [ 45.093467][ T7254] [ 45.095774][ T7254] write to 0xffff888126bf4a2c of 4 bytes by interrupt on cpu 0: [ 45.103382][ T7254] tcp_add_backlog+0x4a0/0xcc0 [ 45.108132][ T7254] tcp_v4_rcv+0x1a60/0x1bb0 [ 45.112671][ T7254] ip_protocol_deliver_rcu+0x4d/0x420 [ 45.118023][ T7254] ip_local_deliver_finish+0x110/0x140 [ 45.123460][ T7254] ip_local_deliver+0x133/0x210 [ 45.128283][ T7254] ip_rcv_finish+0x121/0x160 [ 45.132844][ T7254] ip_rcv+0x18f/0x1a0 [ 45.136803][ T7254] __netif_receive_skb_one_core+0xa7/0xe0 [ 45.142514][ T7254] __netif_receive_skb+0x37/0xf0 [ 45.147431][ T7254] netif_receive_skb_internal+0x59/0x190 [ 45.153054][ T7254] napi_gro_receive+0x28f/0x330 [ 45.157897][ T7254] receive_buf+0x284/0x30b0 [ 45.162378][ T7254] virtnet_poll+0x436/0x7d0 [ 45.166871][ T7254] net_rx_action+0x3ae/0xa90 [ 45.171433][ T7254] [ 45.173743][ T7254] read to 0xffff888126bf4a2c of 4 bytes by task 7254 on cpu 1: [ 45.181259][ T7254] tcp_grow_window.isra.0+0x6b/0x480 [ 45.186531][ T7254] tcp_event_data_recv+0x68f/0x990 [ 45.191619][ T7254] tcp_data_queue+0x13f6/0x20b0 [ 45.196470][ T7254] tcp_rcv_established+0x517/0xf50 [ 45.201561][ T7254] tcp_v4_do_rcv+0x381/0x4e0 [ 45.206147][ T7254] __release_sock+0x135/0x1e0 [ 45.210805][ T7254] release_sock+0x61/0x160 [ 45.215206][ T7254] tcp_recvmsg+0x63b/0x1a30 [ 45.219715][ T7254] inet_recvmsg+0xbb/0x250 [ 45.224116][ T7254] sock_recvmsg+0x92/0xb0 [ 45.228516][ T7254] sock_read_iter+0x15f/0x1e0 [ 45.233189][ T7254] new_sync_read+0x389/0x4f0 [ 45.237868][ T7254] __vfs_read+0xb1/0xc0 [ 45.241998][ T7254] [ 45.244363][ T7254] Reported by Kernel Concurrency Sanitizer on: [ 45.250515][ T7254] CPU: 1 PID: 7254 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 45.257947][ T7254] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.268040][ T7254] ================================================================== [ 45.276197][ T7254] Kernel panic - not syncing: panic_on_warn set ... [ 45.282770][ T7254] CPU: 1 PID: 7254 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 45.290226][ T7254] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.300305][ T7254] Call Trace: [ 45.303586][ T7254] dump_stack+0xf5/0x159 [ 45.307814][ T7254] panic+0x210/0x640 [ 45.311713][ T7254] ? inet_recvmsg+0xbb/0x250 [ 45.316286][ T7254] ? vprintk_func+0x8d/0x140 [ 45.320856][ T7254] kcsan_report.cold+0xc/0x10 [ 45.325513][ T7254] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 45.331051][ T7254] __tsan_read4+0x2c/0x30 [ 45.335536][ T7254] tcp_grow_window.isra.0+0x6b/0x480 [ 45.340795][ T7254] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 45.346417][ T7254] tcp_event_data_recv+0x68f/0x990 [ 45.351545][ T7254] ? __bpf_offload_dev_match.isra.0+0x5d0/0x640 [ 45.357771][ T7254] tcp_data_queue+0x13f6/0x20b0 [ 45.362600][ T7254] ? tcp_urg+0xa1/0x5c0 [ 45.366736][ T7254] tcp_rcv_established+0x517/0xf50 [ 45.371830][ T7254] ? ipv4_dst_check+0xc6/0xf0 [ 45.377180][ T7254] tcp_v4_do_rcv+0x381/0x4e0 [ 45.381762][ T7254] __release_sock+0x135/0x1e0 [ 45.386439][ T7254] release_sock+0x61/0x160 [ 45.390860][ T7254] tcp_recvmsg+0x63b/0x1a30 [ 45.395352][ T7254] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 45.400990][ T7254] inet_recvmsg+0xbb/0x250 [ 45.405391][ T7254] ? __tsan_read8+0x2c/0x30 [ 45.409892][ T7254] ? inet_sendpage+0x100/0x100 [ 45.414637][ T7254] sock_recvmsg+0x92/0xb0 [ 45.418946][ T7254] sock_read_iter+0x15f/0x1e0 [ 45.423779][ T7254] new_sync_read+0x389/0x4f0 [ 45.428367][ T7254] __vfs_read+0xb1/0xc0 [ 45.432505][ T7254] vfs_read+0x143/0x2c0 [ 45.436644][ T7254] ksys_read+0xd5/0x1b0 [ 45.440791][ T7254] __x64_sys_read+0x4c/0x60 [ 45.445311][ T7254] do_syscall_64+0xcc/0x370 [ 45.449807][ T7254] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 45.455675][ T7254] RIP: 0033:0x47c530 [ 45.459546][ T7254] 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 [ 45.479226][ T7254] RSP: 002b:000000c4203077d8 EFLAGS: 00000212 ORIG_RAX: 0000000000000000 [ 45.487632][ T7254] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 45.495592][ T7254] RDX: 0000000000001000 RSI: 000000c420156000 RDI: 0000000000000003 [ 45.503541][ T7254] RBP: 000000c420307830 R08: 0000000000000000 R09: 0000000000000000 [ 45.511486][ T7254] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000040 [ 45.519488][ T7254] R13: ffffffffffffffff R14: 0000000000000008 R15: ffffffffffffffff [ 45.529139][ T7254] Kernel Offset: disabled [ 45.533510][ T7254] Rebooting in 86400 seconds..