[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 38.429925][ T26] audit: type=1800 audit(1572666181.360:25): pid=7087 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 38.482229][ T26] audit: type=1800 audit(1572666181.360:26): pid=7087 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 38.509430][ T26] audit: type=1800 audit(1572666181.360:27): pid=7087 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 '10.128.0.177' (ECDSA) to the list of known hosts. 2019/11/02 03:43:09 fuzzer started 2019/11/02 03:43:11 dialing manager at 10.128.0.105:41349 2019/11/02 03:43:11 syscalls: 2540 2019/11/02 03:43:11 code coverage: enabled 2019/11/02 03:43:11 comparison tracing: enabled 2019/11/02 03:43:11 extra coverage: extra coverage is not supported by the kernel 2019/11/02 03:43:11 setuid sandbox: enabled 2019/11/02 03:43:11 namespace sandbox: enabled 2019/11/02 03:43:11 Android sandbox: /sys/fs/selinux/policy does not exist 2019/11/02 03:43:11 fault injection: enabled 2019/11/02 03:43:11 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/11/02 03:43:11 net packet injection: enabled 2019/11/02 03:43:11 net device setup: enabled 2019/11/02 03:43:11 concurrency sanitizer: enabled syzkaller login: [ 52.353698][ T7250] KCSAN: could not find function: 'poll_schedule_timeout' 2019/11/02 03:43:32 adding functions to KCSAN blacklist: '__do_page_fault' 'task_dump_owner' 'blk_mq_run_hw_queue' 'kauditd_thread' '__skb_try_recv_from_queue' 'virtqueue_get_buf_ctx' 'do_wait' 'snd_seq_prioq_cell_out' 'rcu_gp_fqs_check_wake' 'tick_nohz_idle_stop_tick' 'fasync_remove_entry' 'osq_lock' '__alloc_file' 'page_counter_try_charge' 'ext4_da_write_end' 'ext4_free_inode' 'find_next_bit' 'poll_schedule_timeout' 'datagram_poll' 'blk_mq_dispatch_rq_list' '__snd_rawmidi_transmit_ack' '__add_to_page_cache_locked' 'pipe_wait' 'ep_poll' 'generic_fillattr' 'generic_write_end' 'echo_char' 'integrity_iint_find' 'mm_update_next_owner' 'install_new_memslots' 'balance_dirty_pages' 'atime_needs_update' 'tcp_add_backlog' 'vm_area_dup' 'process_srcu' '__find_get_block' 'shmem_add_to_page_cache' 'sit_tunnel_xmit' 'audit_log_start' 'generic_permission' 'iput' 'blk_mq_sched_dispatch_requests' 'shmem_file_read_iter' 'mod_timer' 'taskstats_exit' 'ext4_has_free_clusters' 'xas_clear_mark' 'snd_seq_check_queue' 'pid_update_inode' 'tomoyo_supervisor' 'tick_sched_do_timer' 'copy_process' 'update_defense_level' '__acct_update_integrals' 'ksys_read' '__dev_queue_xmit' 'kvm_write_tsc' 'wbt_issue' 'blk_stat_add' '__dentry_kill' '__nf_conntrack_find_get' 'ktime_get_real_seconds' 'find_get_pages_range_tag' 'n_tty_receive_buf_common' 'run_timer_softirq' 'add_timer' 'xas_find_marked' 'p9_poll_workfn' 'tcp_v4_rcv' 'ext4_nonda_switch' 'add_timer_on' 'ext4_mark_iloc_dirty' 'ext4_setattr' '__filemap_fdatawrite_range' 'exit_signals' '__hrtimer_run_queues' '__delete_from_page_cache' 'list_lru_count_one' 'shmem_getpage_gfp' 'do_syslog' 'ext4_free_inodes_count' 'rcu_gp_fqs_loop' 'snapshot_refaults' '__mark_inode_dirty' 'dd_has_work' 'timer_clear_idle' 'common_perm_cond' 'pipe_poll' 'tcp_poll' '__ext4_new_inode' 'ktime_get_seconds' 'icmp_global_allow' '__skb_wait_for_more_packets' '__rb_erase_color' 'tick_do_update_jiffies64' '__nf_ct_refresh_acct' 'blk_mq_get_request' 'do_nanosleep' 'kernfs_refresh_inode' 'mem_cgroup_select_victim_node' 'inet_putpeer' [ 219.644949][ T7240] ================================================================== [ 219.653264][ T7240] BUG: KCSAN: data-race in handle_mm_fault / watchdog [ 219.660033][ T7240] [ 219.662344][ T7240] read to 0xffff88812aa69110 of 8 bytes by task 1060 on cpu 1: [ 219.669862][ T7240] watchdog+0x2c3/0x7c0 [ 219.674020][ T7240] kthread+0x1d4/0x200 [ 219.678077][ T7240] ret_from_fork+0x1f/0x30 [ 219.682513][ T7240] [ 219.684823][ T7240] write to 0xffff88812aa69110 of 8 bytes by task 7240 on cpu 0: [ 219.692435][ T7240] handle_mm_fault+0x4a/0x530 [ 219.697092][ T7240] __do_page_fault+0x3fb/0x9e0 [ 219.701881][ T7240] do_page_fault+0x54/0x233 [ 219.706357][ T7240] page_fault+0x34/0x40 [ 219.710485][ T7240] [ 219.712935][ T7240] Reported by Kernel Concurrency Sanitizer on: [ 219.719072][ T7240] CPU: 0 PID: 7240 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 219.726699][ T7240] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 219.736751][ T7240] ================================================================== [ 219.744792][ T7240] Kernel panic - not syncing: panic_on_warn set ... [ 219.751358][ T7240] CPU: 0 PID: 7240 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 219.758785][ T7240] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 219.768813][ T7240] Call Trace: [ 219.772096][ T7240] dump_stack+0xf5/0x159 [ 219.776318][ T7240] panic+0x210/0x640 [ 219.780194][ T7240] ? vprintk_func+0x8d/0x140 [ 219.784761][ T7240] kcsan_report.cold+0xc/0x10 [ 219.789418][ T7240] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 219.794940][ T7240] __tsan_write8+0x32/0x40 [ 219.799332][ T7240] handle_mm_fault+0x4a/0x530 [ 219.803996][ T7240] __do_page_fault+0x3fb/0x9e0 [ 219.808740][ T7240] do_page_fault+0x54/0x233 [ 219.813233][ T7240] ? prepare_exit_to_usermode+0x154/0x1a0 [ 219.818932][ T7240] page_fault+0x34/0x40 [ 219.823061][ T7240] RIP: 0033:0x45a2a3 [ 219.827381][ T7240] Code: 00 48 81 eb 00 01 00 00 48 81 c7 00 01 00 00 48 81 fb 00 01 00 00 73 82 e9 07 ff ff ff c5 fd ef c0 48 81 fb 00 00 00 02 73 46 fe 7f 07 c5 fe 7f 47 20 c5 fe 7f 47 40 c5 fe 7f 47 60 48 81 eb [ 219.846974][ T7240] RSP: 002b:000000c420145e98 EFLAGS: 00010202 [ 219.853023][ T7240] RAX: 0000000000000000 RBX: 0000000000005000 RCX: 000000000000c000 [ 219.860968][ T7240] RDX: 0000000000000000 RSI: 000000000000001b RDI: 000000c433297000 [ 219.869007][ T7240] RBP: 000000c420145ee0 R08: 000000c000000000 R09: 000000000000994d [ 219.876956][ T7240] R10: 00007f42bef24be8 R11: 07ffffffffffffff R12: 0000000000000000 [ 219.884902][ T7240] R13: 0000000000000005 R14: 0000000000000005 R15: 0000000000000005 [ 219.894748][ T7240] Kernel Offset: disabled [ 219.899084][ T7240] Rebooting in 86400 seconds..