[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [ 49.338432][ T7899] sshd (7899) used greatest stack depth: 10136 bytes left [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 49.549130][ T27] kauditd_printk_skb: 6 callbacks suppressed [ 49.549148][ T27] audit: type=1800 audit(1581442236.911:29): pid=7832 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 [ 49.575326][ T27] audit: type=1800 audit(1581442236.911:30): pid=7832 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 '10.128.10.48' (ECDSA) to the list of known hosts. 2020/02/11 17:30:47 fuzzer started 2020/02/11 17:30:49 dialing manager at 10.128.0.105:33799 2020/02/11 17:30:51 syscalls: 2904 2020/02/11 17:30:51 code coverage: enabled 2020/02/11 17:30:51 comparison tracing: enabled 2020/02/11 17:30:51 extra coverage: enabled 2020/02/11 17:30:51 setuid sandbox: enabled 2020/02/11 17:30:51 namespace sandbox: enabled 2020/02/11 17:30:51 Android sandbox: /sys/fs/selinux/policy does not exist 2020/02/11 17:30:51 fault injection: enabled 2020/02/11 17:30:51 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2020/02/11 17:30:51 net packet injection: enabled 2020/02/11 17:30:51 net device setup: enabled 2020/02/11 17:30:51 concurrency sanitizer: enabled 2020/02/11 17:30:51 devlink PCI setup: PCI device 0000:00:10.0 is not available 2020/02/11 17:30:52 adding functions to KCSAN blacklist: 'do_syslog' 'tick_do_update_jiffies64' 'tomoyo_supervisor' 'find_get_pages_range_tag' 'kauditd_thread' 'wbt_done' 'generic_write_end' 'ep_poll' 'pcpu_alloc' 'ext4_has_free_clusters' 'mod_timer' syzkaller login: [ 75.726430][ T0] ================================================================== [ 75.734591][ T0] BUG: KCSAN: data-race in tick_nohz_next_event / tick_sched_do_timer [ 75.742836][ T0] [ 75.745268][ T0] write to 0xffffffff85ebb050 of 4 bytes by interrupt on cpu 0: [ 75.752913][ T0] tick_sched_do_timer+0xc0/0xe0 [ 75.757984][ T0] tick_sched_timer+0x43/0xe0 [ 75.762896][ T0] __hrtimer_run_queues+0x274/0x5f0 [ 75.768108][ T0] hrtimer_interrupt+0x22a/0x480 [ 75.773074][ T0] smp_apic_timer_interrupt+0xdc/0x280 [ 75.778547][ T0] apic_timer_interrupt+0xf/0x20 [ 75.783514][ T0] __tsan_read8+0x34/0x100 [ 75.787947][ T0] nf_nat_ipv4_fn+0x32/0x160 [ 75.792841][ T0] nf_nat_ipv4_in+0x75/0x100 [ 75.799181][ T0] nf_hook_slow+0x83/0x160 [ 75.803603][ T0] nf_hook_slow_list+0x139/0x285 [ 75.808978][ T0] ip_sublist_rcv+0x510/0x550 [ 75.814072][ T0] ip_list_rcv+0x2f5/0x322 [ 75.818508][ T0] __netif_receive_skb_list_core+0x350/0x5c0 [ 75.824484][ T0] netif_receive_skb_list_internal+0x5d8/0x830 [ 75.831097][ T0] gro_normal_list.part.0+0x3a/0xb0 [ 75.836374][ T0] gro_normal_one+0x162/0x170 [ 75.841049][ T0] napi_gro_receive+0x288/0x300 [ 75.845889][ T0] receive_buf+0x284/0x30b0 [ 75.850579][ T0] virtnet_poll+0x436/0x7d0 [ 75.855161][ T0] net_rx_action+0x3ae/0xa90 [ 75.859774][ T0] __do_softirq+0x115/0x33f [ 75.864260][ T0] run_ksoftirqd+0x46/0x60 [ 75.868664][ T0] smpboot_thread_fn+0x37d/0x4a0 [ 75.873590][ T0] kthread+0x1d4/0x200 [ 75.877666][ T0] ret_from_fork+0x1f/0x30 [ 75.882071][ T0] [ 75.884386][ T0] read to 0xffffffff85ebb050 of 4 bytes by task 0 on cpu 1: [ 75.891676][ T0] tick_nohz_next_event+0x19d/0x370 [ 75.896896][ T0] tick_nohz_idle_stop_tick+0x3c2/0x670 [ 75.903112][ T0] do_idle+0x1b8/0x290 [ 75.907613][ T0] cpu_startup_entry+0x1b/0x20 [ 75.912368][ T0] start_secondary+0x168/0x1b0 [ 75.917114][ T0] secondary_startup_64+0xa4/0xb0 [ 75.922116][ T0] [ 75.924423][ T0] Reported by Kernel Concurrency Sanitizer on: [ 75.930565][ T0] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.5.0-rc1-syzkaller #0 [ 75.938443][ T0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.948494][ T0] ================================================================== [ 75.956556][ T0] Kernel panic - not syncing: panic_on_warn set ... [ 75.963129][ T0] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.5.0-rc1-syzkaller #0 [ 75.971001][ T0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.981184][ T0] Call Trace: [ 75.984477][ T0] dump_stack+0x11d/0x181 [ 75.988803][ T0] panic+0x210/0x640 [ 75.992685][ T0] ? vprintk_func+0x8d/0x140 [ 75.997269][ T0] kcsan_report.cold+0xc/0x15 [ 76.001942][ T0] kcsan_setup_watchpoint+0x2e2/0x380 [ 76.007319][ T0] __tsan_read4+0xc6/0x100 [ 76.011723][ T0] tick_nohz_next_event+0x19d/0x370 [ 76.016996][ T0] tick_nohz_idle_stop_tick+0x3c2/0x670 [ 76.022527][ T0] ? debug_smp_processor_id+0x43/0x137 [ 76.027982][ T0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.034206][ T0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.040433][ T0] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 76.046668][ T0] do_idle+0x1b8/0x290 [ 76.050719][ T0] ? debug_smp_processor_id+0x3e/0x137 [ 76.056201][ T0] cpu_startup_entry+0x1b/0x20 [ 76.061018][ T0] start_secondary+0x168/0x1b0 [ 76.065869][ T0] secondary_startup_64+0xa4/0xb0 [ 76.072296][ T0] Kernel Offset: disabled [ 76.076626][ T0] Rebooting in 86400 seconds..