[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 51.913853][ T26] kauditd_printk_skb: 7 callbacks suppressed [ 51.913868][ T26] audit: type=1800 audit(1575473404.612:29): pid=7460 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2465 res=0 [ 51.940104][ T26] audit: type=1800 audit(1575473404.612:30): pid=7460 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2456 res=0 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.150' (ECDSA) to the list of known hosts. 2019/12/04 15:30:15 fuzzer started 2019/12/04 15:30:17 dialing manager at 10.128.0.105:44241 2019/12/04 15:30:21 syscalls: 2684 2019/12/04 15:30:21 code coverage: enabled 2019/12/04 15:30:21 comparison tracing: enabled 2019/12/04 15:30:21 extra coverage: extra coverage is not supported by the kernel 2019/12/04 15:30:21 setuid sandbox: enabled 2019/12/04 15:30:21 namespace sandbox: enabled 2019/12/04 15:30:21 Android sandbox: /sys/fs/selinux/policy does not exist 2019/12/04 15:30:21 fault injection: enabled 2019/12/04 15:30:21 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/12/04 15:30:21 net packet injection: enabled 2019/12/04 15:30:21 net device setup: enabled 2019/12/04 15:30:21 concurrency sanitizer: enabled 2019/12/04 15:30:21 devlink PCI setup: PCI device 0000:00:10.0 is not available syzkaller login: [ 69.664017][ T7628] KCSAN: could not find function: 'poll_schedule_timeout' 2019/12/04 15:30:30 adding functions to KCSAN blacklist: 'blk_mq_run_hw_queue' 'rcu_gp_fqs_check_wake' 'tick_do_update_jiffies64' 'lruvec_lru_size' 'ep_poll' 'ext4_free_inodes_count' 'poll_schedule_timeout' '__writeback_single_inode' 'do_nanosleep' 'xas_clear_mark' 'generic_fillattr' 'taskstats_exit' 'copy_process' 'do_exit' 'tick_nohz_idle_stop_tick' 'run_timer_softirq' 'generic_write_end' 'ext4_free_inode' 'kauditd_thread' 'tick_sched_do_timer' 'page_counter_try_charge' 'add_timer' 'pipe_wait' 'xas_find_marked' 'find_next_bit' 'n_tty_receive_buf_common' 'mod_timer' 'pid_update_inode' 'fprop_fraction_percpu' 'tomoyo_supervisor' '__hrtimer_run_queues' '__snd_rawmidi_transmit_ack' 'blk_mq_get_request' 'sit_tunnel_xmit' 'common_perm_cond' 'ktime_get_real_seconds' '__ext4_new_inode' 'blk_mq_dispatch_rq_list' 'ext4_has_free_clusters' 'wbt_done' '__rb_insert_augmented' '__filemap_fdatawrite_range' 'find_get_pages_range_tag' 'futex_wait_queue_me' 'shmem_getpage_gfp' 'mem_cgroup_select_victim_node' 'pipe_poll' 'ext4_nonda_switch' 'sctp_assoc_migrate' 'tomoyo_check_path_acl' 'audit_log_start' '__splice_from_pipe' 'dd_has_work' 'tcp_add_backlog' [ 89.016535][ T7625] ================================================================== [ 89.024701][ T7625] BUG: KCSAN: data-race in handle_mm_fault / watchdog [ 89.031460][ T7625] [ 89.033802][ T7625] read to 0xffff888126b6a110 of 8 bytes by task 1069 on cpu 1: [ 89.041374][ T7625] watchdog+0x2c3/0x7c0 [ 89.045526][ T7625] kthread+0x1d4/0x200 [ 89.049599][ T7625] ret_from_fork+0x1f/0x30 [ 89.053996][ T7625] [ 89.056337][ T7625] write to 0xffff888126b6a110 of 8 bytes by task 7625 on cpu 0: [ 89.063976][ T7625] handle_mm_fault+0x4a/0x530 [ 89.068793][ T7625] __do_page_fault+0x456/0x8d0 [ 89.073681][ T7625] do_page_fault+0x38/0x194 [ 89.078189][ T7625] page_fault+0x34/0x40 [ 89.082326][ T7625] [ 89.084654][ T7625] Reported by Kernel Concurrency Sanitizer on: [ 89.090799][ T7625] CPU: 0 PID: 7625 Comm: syz-fuzzer Not tainted 5.4.0-syzkaller #0 [ 89.098769][ T7625] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 89.108820][ T7625] ================================================================== [ 89.116870][ T7625] Kernel panic - not syncing: panic_on_warn set ... [ 89.123448][ T7625] CPU: 0 PID: 7625 Comm: syz-fuzzer Not tainted 5.4.0-syzkaller #0 [ 89.131322][ T7625] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 89.141365][ T7625] Call Trace: [ 89.144651][ T7625] dump_stack+0x11d/0x181 [ 89.148977][ T7625] panic+0x210/0x640 [ 89.152865][ T7625] ? vprintk_func+0x8d/0x140 [ 89.157451][ T7625] kcsan_report.cold+0xc/0xd [ 89.162049][ T7625] kcsan_setup_watchpoint+0x3fe/0x460 [ 89.167418][ T7625] __tsan_unaligned_write8+0xc4/0x100 [ 89.172785][ T7625] handle_mm_fault+0x4a/0x530 [ 89.177462][ T7625] __do_page_fault+0x456/0x8d0 [ 89.182221][ T7625] do_page_fault+0x38/0x194 [ 89.186738][ T7625] page_fault+0x34/0x40 [ 89.190881][ T7625] RIP: 0033:0x41d194 [ 89.194770][ T7625] Code: 48 83 c6 08 49 83 f8 08 0f 8d e7 00 00 00 48 39 de 0f 83 de 00 00 00 0f ba e2 00 0f 83 ca 00 00 00 4c 8b 4c 24 78 4e 8d 14 0e <4d> 8b 12 4d 85 d2 74 c9 4c 39 d0 77 c4 49 39 ca 73 bf 4c 89 44 24 [ 89.214368][ T7625] RSP: 002b:000000c4203c9e10 EFLAGS: 00010287 [ 89.220428][ T7625] RAX: 000000c420000000 RBX: 0000000000040000 RCX: 000000c422940000 [ 89.229356][ T7625] RDX: 0000000000000029 RSI: 0000000000023000 RDI: 00007f251100b000 [ 89.237437][ T7625] RBP: 000000c4203c9e78 R08: 0000000000000000 R09: 0000000000d79000 [ 89.245415][ T7625] R10: 0000000000d9c000 R11: 000000c4203c9fc0 R12: 000000c421fa39b8 [ 89.253402][ T7625] R13: 000000000000000f R14: 0000000000c27320 R15: 0000000000000a81 [ 89.262692][ T7625] Kernel Offset: disabled [ 89.267042][ T7625] Rebooting in 86400 seconds..