[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 61.820825][ T27] audit: type=1800 audit(1578448096.496:25): pid=7604 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 61.840605][ T27] audit: type=1800 audit(1578448096.496:26): pid=7604 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 61.860768][ T27] audit: type=1800 audit(1578448096.496:27): pid=7604 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 '10.128.0.129' (ECDSA) to the list of known hosts. 2020/01/08 01:48:25 fuzzer started 2020/01/08 01:48:26 dialing manager at 10.128.0.105:46717 2020/01/08 01:48:26 syscalls: 2808 2020/01/08 01:48:26 code coverage: enabled 2020/01/08 01:48:26 comparison tracing: enabled 2020/01/08 01:48:26 extra coverage: enabled 2020/01/08 01:48:26 setuid sandbox: enabled 2020/01/08 01:48:26 namespace sandbox: enabled 2020/01/08 01:48:26 Android sandbox: /sys/fs/selinux/policy does not exist 2020/01/08 01:48:26 fault injection: enabled 2020/01/08 01:48:26 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2020/01/08 01:48:26 net packet injection: enabled 2020/01/08 01:48:26 net device setup: enabled 2020/01/08 01:48:26 concurrency sanitizer: enabled 2020/01/08 01:48:26 devlink PCI setup: PCI device 0000:00:10.0 is not available syzkaller login: [ 74.811575][ T7772] KCSAN: could not find function: 'poll_schedule_timeout' 2020/01/08 01:48:35 adding functions to KCSAN blacklist: 'mod_timer' 'generic_fillattr' '__perf_event_overflow' '__hrtimer_run_queues' 'ktime_get_ts64' 'virtqueue_disable_cb' 'evict' 'tomoyo_supervisor' 'shmem_add_to_page_cache' 'ext4_free_inodes_count' '__do_page_cache_readahead' 'copy_process' 'sbitmap_queue_clear' 'generic_permission' '__ext4_new_inode' 'ep_poll' 'do_nanosleep' 'tick_sched_do_timer' 'poll_schedule_timeout' '__snd_rawmidi_transmit_ack' 'fasync_remove_entry' 'audit_log_start' 'run_timer_softirq' 'kauditd_thread' 'ktime_get_real_seconds' 'pid_update_inode' 'pcpu_alloc' 'ext4_mb_good_group' 'echo_char' 'find_get_pages_range_tag' 'can_send' 'vm_area_dup' 'mm_update_next_owner' 'blk_mq_get_request' 'blk_mq_sched_dispatch_requests' 'do_syslog' 'inode_sync_complete' '__add_to_page_cache_locked' 'rcu_gp_fqs_loop' '__mark_inode_dirty' 'futex_wait_queue_me' 'iomap_dio_bio_actor' 'find_next_bit' 'sit_tunnel_xmit' 'timer_clear_idle' 'ext4_nonda_switch' 'blk_mq_dispatch_rq_list' 'taskstats_exit' 'rcu_gp_fqs_check_wake' 'dd_has_work' 'ext4_has_free_clusters' 'add_timer' 'blk_mq_run_hw_queue' 'unix_release_sock' 'generic_write_end' 'xas_clear_mark' 'do_exit' 'ext4_free_inode' 'tick_nohz_idle_stop_tick' 'n_tty_receive_buf_common' 'tick_nohz_next_event' 'tick_do_update_jiffies64' 'ext4_mark_iloc_dirty' 'wbt_done' [ 201.682924][ T616] ================================================================== [ 201.691333][ T616] BUG: KCSAN: data-race in schedule_hrtimeout_range_clock / watchdog [ 201.699376][ T616] [ 201.701694][ T616] write to 0xffff88811e3eb050 of 8 bytes by task 7757 on cpu 1: [ 201.709313][ T616] schedule_hrtimeout_range_clock+0x14e/0x1e0 [ 201.715367][ T616] schedule_hrtimeout_range+0x34/0x50 [ 201.720726][ T616] poll_schedule_timeout.constprop.0+0x75/0xc0 [ 201.726865][ T616] do_select+0xd7f/0x1020 [ 201.731290][ T616] core_sys_select+0x312/0x650 [ 201.736101][ T616] do_pselect.constprop.0+0x11d/0x160 [ 201.741462][ T616] __x64_sys_pselect6+0x12e/0x170 [ 201.746471][ T616] do_syscall_64+0xcc/0x3a0 [ 201.750962][ T616] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 201.756832][ T616] [ 201.759339][ T616] read to 0xffff88811e3eb050 of 8 bytes by task 616 on cpu 0: [ 201.766801][ T616] watchdog+0x2b1/0x960 [ 201.770950][ T616] kthread+0x1d4/0x200 [ 201.775011][ T616] ret_from_fork+0x1f/0x30 [ 201.779407][ T616] [ 201.781721][ T616] Reported by Kernel Concurrency Sanitizer on: [ 201.787863][ T616] CPU: 0 PID: 616 Comm: khungtaskd Not tainted 5.5.0-rc1-syzkaller #0 [ 201.795993][ T616] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 201.806053][ T616] ================================================================== [ 201.814097][ T616] Kernel panic - not syncing: panic_on_warn set ... [ 201.820773][ T616] CPU: 0 PID: 616 Comm: khungtaskd Not tainted 5.5.0-rc1-syzkaller #0 [ 201.828910][ T616] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 201.838950][ T616] Call Trace: [ 201.842477][ T616] dump_stack+0x11d/0x181 [ 201.846843][ T616] panic+0x210/0x640 [ 201.850786][ T616] ? vprintk_func+0x8d/0x140 [ 201.855370][ T616] kcsan_report.cold+0xc/0xd [ 201.859999][ T616] kcsan_setup_watchpoint+0x3fe/0x460 [ 201.865363][ T616] __tsan_read8+0xc6/0x100 [ 201.869774][ T616] watchdog+0x2b1/0x960 [ 201.873922][ T616] ? constant_test_bit+0x12/0x30 [ 201.878849][ T616] kthread+0x1d4/0x200 [ 201.882909][ T616] ? __read_once_size.constprop.0+0x20/0x20 [ 201.888797][ T616] ? kthread_unpark+0xe0/0xe0 [ 201.893461][ T616] ret_from_fork+0x1f/0x30 [ 201.899168][ T616] Kernel Offset: disabled [ 201.903497][ T616] Rebooting in 86400 seconds..