[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 39.266845][ T26] audit: type=1800 audit(1572816698.913:25): pid=7024 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 39.302426][ T26] audit: type=1800 audit(1572816698.913:26): pid=7024 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [ 40.158747][ T7100] sshd (7100) used greatest stack depth: 10136 bytes left [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.69' (ECDSA) to the list of known hosts. 2019/11/03 21:31:50 fuzzer started 2019/11/03 21:31:52 dialing manager at 10.128.0.105:42255 2019/11/03 21:31:53 syscalls: 2553 2019/11/03 21:31:53 code coverage: enabled 2019/11/03 21:31:53 comparison tracing: enabled 2019/11/03 21:31:53 extra coverage: extra coverage is not supported by the kernel 2019/11/03 21:31:53 setuid sandbox: enabled 2019/11/03 21:31:53 namespace sandbox: enabled 2019/11/03 21:31:53 Android sandbox: /sys/fs/selinux/policy does not exist 2019/11/03 21:31:53 fault injection: enabled 2019/11/03 21:31:53 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/11/03 21:31:53 net packet injection: enabled 2019/11/03 21:31:53 net device setup: enabled 2019/11/03 21:31:53 concurrency sanitizer: enabled 2019/11/03 21:31:53 devlink PCI setup: PCI device 0000:00:10.0 is not available 2019/11/03 21:31:55 adding functions to KCSAN blacklist: 'ext4_free_inode' 'tcp_add_backlog' 'generic_write_end' 'blk_mq_get_request' 'get_wchan' 'audit_log_start' 'find_next_bit' 'generic_permission' 'ktime_get_real_seconds' '__tcp_select_window' 'pid_update_inode' 'tomoyo_supervisor' '__splice_from_pipe' '__hrtimer_run_queues' syzkaller login: [ 56.497762][ T7178] ================================================================== [ 56.506086][ T7178] BUG: KCSAN: data-race in tcp_poll / tcp_queue_rcv [ 56.513452][ T7178] [ 56.515794][ T7178] write to 0xffff8881220a5778 of 4 bytes by interrupt on cpu 0: [ 56.523602][ T7178] tcp_queue_rcv+0x180/0x380 [ 56.529439][ T7178] tcp_rcv_established+0xbf1/0xf50 [ 56.535585][ T7178] tcp_v4_do_rcv+0x381/0x4e0 [ 56.540604][ T7178] tcp_v4_rcv+0x19dc/0x1bb0 [ 56.545214][ T7178] ip_protocol_deliver_rcu+0x4d/0x420 [ 56.550867][ T7178] ip_local_deliver_finish+0x110/0x140 [ 56.556443][ T7178] ip_local_deliver+0x133/0x210 [ 56.561376][ T7178] ip_rcv_finish+0x121/0x160 [ 56.566782][ T7178] ip_rcv+0x18f/0x1a0 [ 56.571623][ T7178] __netif_receive_skb_one_core+0xa7/0xe0 [ 56.579118][ T7178] __netif_receive_skb+0x37/0xf0 [ 56.584503][ T7178] netif_receive_skb_internal+0x59/0x190 [ 56.590603][ T7178] napi_gro_receive+0x28f/0x330 [ 56.596126][ T7178] receive_buf+0x284/0x30b0 [ 56.601301][ T7178] [ 56.604379][ T7178] read to 0xffff8881220a5778 of 4 bytes by task 7178 on cpu 1: [ 56.613695][ T7178] tcp_poll+0x204/0x6b0 [ 56.619259][ T7178] sock_poll+0xed/0x250 [ 56.624953][ T7178] ep_item_poll.isra.0+0x90/0x190 [ 56.630992][ T7178] ep_send_events_proc+0x113/0x590 [ 56.636492][ T7178] ep_scan_ready_list.constprop.0+0x189/0x500 [ 56.644135][ T7178] ep_poll+0xe3/0x900 [ 56.648940][ T7178] do_epoll_wait+0x162/0x180 [ 56.655287][ T7178] __x64_sys_epoll_pwait+0xcd/0x180 [ 56.660847][ T7178] do_syscall_64+0xcc/0x370 [ 56.666536][ T7178] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 56.673557][ T7178] [ 56.676153][ T7178] Reported by Kernel Concurrency Sanitizer on: [ 56.683133][ T7178] CPU: 1 PID: 7178 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 56.692439][ T7178] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 56.703063][ T7178] ================================================================== [ 56.711917][ T7178] Kernel panic - not syncing: panic_on_warn set ... [ 56.718578][ T7178] CPU: 1 PID: 7178 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 56.726231][ T7178] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 56.736464][ T7178] Call Trace: [ 56.739747][ T7178] dump_stack+0xf5/0x159 [ 56.743978][ T7178] panic+0x210/0x640 [ 56.747920][ T7178] ? do_syscall_64+0xcc/0x370 [ 56.752596][ T7178] ? vprintk_func+0x8d/0x140 [ 56.757401][ T7178] kcsan_report.cold+0xc/0x10 [ 56.762179][ T7178] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 56.768070][ T7178] ? tcp_recvmsg+0x65b/0x1a30 [ 56.772925][ T7178] __tsan_read4+0x2c/0x30 [ 56.777859][ T7178] tcp_poll+0x204/0x6b0 [ 56.782001][ T7178] ? tcp_alloc_md5sig_pool+0x320/0x320 [ 56.787619][ T7178] sock_poll+0xed/0x250 [ 56.791762][ T7178] ? sock_read_iter+0x1e0/0x1e0 [ 56.796610][ T7178] ep_item_poll.isra.0+0x90/0x190 [ 56.801634][ T7178] ep_send_events_proc+0x113/0x590 [ 56.806733][ T7178] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 56.812385][ T7178] ep_scan_ready_list.constprop.0+0x189/0x500 [ 56.818618][ T7178] ? ep_loop_check_proc+0x2f0/0x2f0 [ 56.824321][ T7178] ep_poll+0xe3/0x900 [ 56.828835][ T7178] ? __fget+0xb8/0x1d0 [ 56.832900][ T7178] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 56.839154][ T7178] ? __fget_light+0xaf/0x190 [ 56.843820][ T7178] do_epoll_wait+0x162/0x180 [ 56.848854][ T7178] __x64_sys_epoll_pwait+0xcd/0x180 [ 56.854064][ T7178] do_syscall_64+0xcc/0x370 [ 56.858658][ T7178] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 56.865788][ T7178] RIP: 0033:0x45b300 [ 56.869857][ T7178] 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 [ 56.892196][ T7178] RSP: 002b:00007ffe1ab02ca0 EFLAGS: 00000246 ORIG_RAX: 0000000000000119 [ 56.902309][ T7178] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045b300 [ 56.910676][ T7178] RDX: 0000000000000080 RSI: 00007ffe1ab02ce0 RDI: 0000000000000004 [ 56.919627][ T7178] RBP: 00007ffe1ab032e0 R08: 0000000000000000 R09: 0000000000000000 [ 56.928300][ T7178] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000080 [ 56.936634][ T7178] R13: ffffffffffffffff R14: 0000000000000002 R15: ffffffffffffffff [ 56.948815][ T7178] Kernel Offset: disabled [ 56.953429][ T7178] Rebooting in 86400 seconds..