[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 37.836059][ T25] audit: type=1800 audit(1572437876.125:25): pid=7122 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 37.855656][ T25] audit: type=1800 audit(1572437876.125:26): pid=7122 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 37.855675][ T25] audit: type=1800 audit(1572437876.125:27): pid=7122 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 '10.128.15.195' (ECDSA) to the list of known hosts. 2019/10/30 12:18:05 fuzzer started 2019/10/30 12:18:07 dialing manager at 10.128.0.105:40771 2019/10/30 12:18:07 syscalls: 2540 2019/10/30 12:18:07 code coverage: enabled 2019/10/30 12:18:07 comparison tracing: enabled 2019/10/30 12:18:07 extra coverage: extra coverage is not supported by the kernel 2019/10/30 12:18:07 setuid sandbox: enabled 2019/10/30 12:18:07 namespace sandbox: enabled 2019/10/30 12:18:07 Android sandbox: /sys/fs/selinux/policy does not exist 2019/10/30 12:18:07 fault injection: enabled 2019/10/30 12:18:07 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/10/30 12:18:07 net packet injection: enabled 2019/10/30 12:18:07 net device setup: enabled 2019/10/30 12:18:07 concurrency sanitizer: enabled syzkaller login: [ 52.979813][ T7292] KCSAN: could not find function: 'poll_schedule_timeout' 2019/10/30 12:18:34 adding functions to KCSAN blacklist: '__hrtimer_run_queues' 'pipe_wait' 'xas_find_marked' '__nf_conntrack_find_get' 'ext4_free_inodes_count' 'sit_tunnel_xmit' '__ext4_new_inode' 'getboottime64' 'kcm_wait_data' 'blk_stat_add' 'relay_switch_subbuf' '__es_shrink' 'poll_schedule_timeout' 'copy_process' 'tomoyo_supervisor' 'blk_mq_get_request' 'snapshot_refaults' 'snd_seq_check_queue' 'tcp_add_backlog' 'ep_poll' 'blk_mq_sched_dispatch_requests' 'shmem_file_read_iter' 'iput' 'delete_from_page_cache_batch' 'list_lru_count_one' '__nf_ct_refresh_acct' 'wbt_done' 'tick_sched_do_timer' 'blk_mq_dispatch_rq_list' 'echo_char' 'ip_finish_output2' '__delete_from_page_cache' 'dd_has_work' 'ktime_get_ts64' 'dst_alloc' '__alloc_file' 'ext4_free_inode' 'get_task_cred' 'tick_nohz_idle_stop_tick' 'blk_mq_free_request' 'shmem_getpage_gfp' 'osq_lock' 'audit_log_start' 'generic_permission' 'vm_area_dup' 'process_srcu' '__mark_inode_dirty' 'commit_echoes' 'kauditd_thread' 'page_counter_try_charge' '__snd_rawmidi_transmit_ack' '__skb_wait_for_more_packets' 'evict' 'ext4_writepages' 'task_dump_owner' 'mod_timer' 'ext4_has_free_clusters' 'generic_file_read_iter' 'mem_cgroup_select_victim_node' 'inet_putpeer' 'generic_write_end' 'tick_do_update_jiffies64' 'rcu_gp_fqs_loop' 'd_alloc_parallel' 'pid_update_inode' 'run_timer_softirq' 'add_timer' 'generic_fillattr' 'list_lru_add' 'taskstats_exit' 'enqueue_timer' 'mm_update_next_owner' '__add_to_page_cache_locked' 'virtqueue_disable_cb' 'balance_dirty_pages' 'rcu_gp_fqs_check_wake' 'bio_endio' '__find_get_block' 'update_defense_level' 'ext4_nonda_switch' 'ext4_da_write_end' 'get_signal' 'tcp_v4_rcv' 'pcpu_alloc' 'install_new_memslots' 'unix_release_sock' 'flush_old_exec' 'udp_set_dev_scratch' 'find_next_bit' 'queue_access_lock' 'pipe_poll' 'p9_poll_workfn' 'sk_wait_data' 'yama_ptracer_del' 'kernfs_refresh_inode' '__dentry_kill' 'tcp_ack' '__blk_queue_split' 'do_nanosleep' 'find_get_pages_range_tag' '__cgroup_account_cputime' 'blk_mq_run_hw_queue' 'ktime_get_seconds' 'icmp_global_allow' 'do_syslog' 'atime_needs_update' 'dccp_rcv_reset' 'xprt_connect' 'n_tty_receive_buf_common' 'snd_seq_prioq_cell_out' 'alloc_pid' 'exit_signals' 'do_readlinkat' '__dev_queue_xmit' 'ext4_mb_good_group' 'mem_cgroup_protected' 'do_exit' 'tcp_poll' 'filemap_map_pages' 'fsnotify' 'do_signal_stop' 'timer_clear_idle' '__skb_try_recv_from_queue' 'ktime_get_with_offset' 'ktime_get_real_seconds' 'find_group_orlov' 'ext4_mark_iloc_dirty' 'snd_ctl_notify' [ 96.183256][ T1061] ================================================================== [ 96.191407][ T1061] BUG: KCSAN: data-race in handle_mm_fault / watchdog [ 96.198323][ T1061] [ 96.200645][ T1061] write to 0xffff88812233d010 of 8 bytes by task 7275 on cpu 1: [ 96.208274][ T1061] handle_mm_fault+0x4a/0x530 [ 96.212943][ T1061] __do_page_fault+0x3fb/0x9e0 [ 96.217701][ T1061] do_page_fault+0x54/0x233 [ 96.222295][ T1061] page_fault+0x34/0x40 [ 96.226435][ T1061] [ 96.228763][ T1061] read to 0xffff88812233d010 of 8 bytes by task 1061 on cpu 0: [ 96.236395][ T1061] watchdog+0x2c3/0x7c0 [ 96.240549][ T1061] kthread+0x1d4/0x200 [ 96.244610][ T1061] ret_from_fork+0x1f/0x30 [ 96.249011][ T1061] [ 96.251336][ T1061] Reported by Kernel Concurrency Sanitizer on: [ 96.258006][ T1061] CPU: 0 PID: 1061 Comm: khungtaskd Not tainted 5.4.0-rc3+ #0 [ 96.265535][ T1061] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 96.276637][ T1061] ================================================================== [ 96.284724][ T1061] Kernel panic - not syncing: panic_on_warn set ... [ 96.291313][ T1061] CPU: 0 PID: 1061 Comm: khungtaskd Not tainted 5.4.0-rc3+ #0 [ 96.298762][ T1061] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 96.308815][ T1061] Call Trace: [ 96.312200][ T1061] dump_stack+0xf5/0x159 [ 96.316450][ T1061] panic+0x210/0x640 [ 96.320351][ T1061] ? vprintk_func+0x8d/0x140 [ 96.325039][ T1061] kcsan_report.cold+0xc/0x10 [ 96.329924][ T1061] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 96.335478][ T1061] __tsan_read8+0x2c/0x30 [ 96.339806][ T1061] watchdog+0x2c3/0x7c0 [ 96.343964][ T1061] kthread+0x1d4/0x200 [ 96.348047][ T1061] ? __read_once_size.constprop.0+0x20/0x20 [ 96.353938][ T1061] ? kthread_stop+0x2d0/0x2d0 [ 96.358620][ T1061] ret_from_fork+0x1f/0x30 [ 96.365010][ T1061] Kernel Offset: disabled [ 96.369344][ T1061] Rebooting in 86400 seconds..