[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 33.781122][ T26] audit: type=1800 audit(1571793325.107:25): pid=7029 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 33.822530][ T26] audit: type=1800 audit(1571793325.107:26): pid=7029 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 33.850994][ T26] audit: type=1800 audit(1571793325.117:27): pid=7029 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 '10.128.1.34' (ECDSA) to the list of known hosts. 2019/10/23 01:15:35 fuzzer started 2019/10/23 01:15:37 dialing manager at 10.128.0.105:33369 2019/10/23 01:15:37 syscalls: 2524 2019/10/23 01:15:37 code coverage: enabled 2019/10/23 01:15:37 comparison tracing: enabled 2019/10/23 01:15:37 extra coverage: extra coverage is not supported by the kernel 2019/10/23 01:15:37 setuid sandbox: enabled 2019/10/23 01:15:37 namespace sandbox: enabled 2019/10/23 01:15:37 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/23 01:15:37 fault injection: enabled 2019/10/23 01:15:37 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/23 01:15:37 net packet injection: enabled 2019/10/23 01:15:37 net device setup: enabled 2019/10/23 01:15:37 concurrency sanitizer: enabled syzkaller login: [ 45.948932][ T7185] ================================================================== [ 45.957115][ T7185] BUG: KCSAN: data-race in __tcp_select_window / tcp_add_backlog [ 45.964918][ T7185] [ 45.967240][ T7185] write to 0xffff88812931a9ec of 4 bytes by interrupt on cpu 0: [ 45.977289][ T7185] tcp_add_backlog+0x4a0/0xcc0 [ 45.982032][ T7185] tcp_v4_rcv+0x1a60/0x1bb0 [ 45.986527][ T7185] ip_protocol_deliver_rcu+0x4d/0x420 [ 45.991878][ T7185] ip_local_deliver_finish+0x110/0x140 [ 45.997428][ T7185] ip_local_deliver+0x133/0x210 [ 46.002264][ T7185] ip_rcv_finish+0x121/0x160 [ 46.006832][ T7185] ip_rcv+0x18f/0x1a0 [ 46.010794][ T7185] __netif_receive_skb_one_core+0xa7/0xe0 [ 46.016490][ T7185] __netif_receive_skb+0x37/0xf0 [ 46.021405][ T7185] netif_receive_skb_internal+0x59/0x190 [ 46.027022][ T7185] napi_gro_receive+0x28f/0x330 [ 46.032029][ T7185] receive_buf+0x284/0x30b0 [ 46.036557][ T7185] virtnet_poll+0x436/0x7d0 [ 46.041472][ T7185] net_rx_action+0x3ae/0xa90 [ 46.046046][ T7185] [ 46.048354][ T7185] read to 0xffff88812931a9ec of 4 bytes by task 7185 on cpu 1: [ 46.055873][ T7185] __tcp_select_window+0x6b/0x4d0 [ 46.060874][ T7185] __tcp_transmit_skb+0x700/0x1d60 [ 46.066106][ T7185] __tcp_send_ack+0x246/0x300 [ 46.070767][ T7185] tcp_send_ack+0x34/0x40 [ 46.075077][ T7185] tcp_cleanup_rbuf+0x130/0x360 [ 46.079924][ T7185] tcp_recvmsg+0x633/0x1a30 [ 46.084425][ T7185] inet_recvmsg+0xbb/0x250 [ 46.088933][ T7185] sock_recvmsg+0x92/0xb0 [ 46.093293][ T7185] sock_read_iter+0x15f/0x1e0 [ 46.097953][ T7185] new_sync_read+0x389/0x4f0 [ 46.102528][ T7185] __vfs_read+0xb1/0xc0 [ 46.107096][ T7185] vfs_read+0x143/0x2c0 [ 46.111227][ T7185] ksys_read+0xd5/0x1b0 [ 46.115367][ T7185] [ 46.117682][ T7185] Reported by Kernel Concurrency Sanitizer on: [ 46.123813][ T7185] CPU: 1 PID: 7185 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 46.131251][ T7185] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.141287][ T7185] ================================================================== [ 46.149336][ T7185] Kernel panic - not syncing: panic_on_warn set ... [ 46.155903][ T7185] CPU: 1 PID: 7185 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 46.163352][ T7185] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.173408][ T7185] Call Trace: [ 46.176688][ T7185] dump_stack+0xf5/0x159 [ 46.180926][ T7185] panic+0x210/0x640 [ 46.184805][ T7185] ? sock_read_iter+0x15f/0x1e0 [ 46.189649][ T7185] ? vprintk_func+0x8d/0x140 [ 46.194220][ T7185] kcsan_report.cold+0xc/0x10 [ 46.198877][ T7185] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 46.204428][ T7185] __tsan_read4+0x2c/0x30 [ 46.208736][ T7185] __tcp_select_window+0x6b/0x4d0 [ 46.213746][ T7185] __tcp_transmit_skb+0x700/0x1d60 [ 46.218839][ T7185] __tcp_send_ack+0x246/0x300 [ 46.223518][ T7185] tcp_send_ack+0x34/0x40 [ 46.228454][ T7185] tcp_cleanup_rbuf+0x130/0x360 [ 46.233288][ T7185] tcp_recvmsg+0x633/0x1a30 [ 46.237785][ T7185] inet_recvmsg+0xbb/0x250 [ 46.242193][ T7185] ? __tsan_read8+0x2c/0x30 [ 46.246687][ T7185] ? inet_sendpage+0x100/0x100 [ 46.251429][ T7185] sock_recvmsg+0x92/0xb0 [ 46.255739][ T7185] sock_read_iter+0x15f/0x1e0 [ 46.260396][ T7185] new_sync_read+0x389/0x4f0 [ 46.264968][ T7185] __vfs_read+0xb1/0xc0 [ 46.269101][ T7185] vfs_read+0x143/0x2c0 [ 46.273247][ T7185] ksys_read+0xd5/0x1b0 [ 46.277394][ T7185] __x64_sys_read+0x4c/0x60 [ 46.281877][ T7185] do_syscall_64+0xcc/0x370 [ 46.286360][ T7185] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 46.292228][ T7185] RIP: 0033:0x47c530 [ 46.296107][ T7185] 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 [ 46.315866][ T7185] RSP: 002b:000000c4202d37d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 [ 46.324256][ T7185] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 46.332303][ T7185] RDX: 0000000000001000 RSI: 000000c420052000 RDI: 0000000000000003 [ 46.340252][ T7185] RBP: 000000c4202d3828 R08: 0000000000000000 R09: 0000000000000000 [ 46.348218][ T7185] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000020 [ 46.356180][ T7185] R13: ffffffffffffffff R14: 0000000000000004 R15: ffffffffffffffff [ 46.365829][ T7185] Kernel Offset: disabled [ 46.370159][ T7185] Rebooting in 86400 seconds..