[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 36.856484][ T25] audit: type=1800 audit(1572633744.352:25): pid=7046 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 36.891018][ T25] audit: type=1800 audit(1572633744.352:26): pid=7046 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 [ 36.923890][ T25] audit: type=1800 audit(1572633744.362:27): pid=7046 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 '10.128.0.29' (ECDSA) to the list of known hosts. 2019/11/01 18:42:34 fuzzer started 2019/11/01 18:42:36 dialing manager at 10.128.0.105:41349 2019/11/01 18:42:37 syscalls: 2540 2019/11/01 18:42:37 code coverage: enabled 2019/11/01 18:42:37 comparison tracing: enabled 2019/11/01 18:42:37 extra coverage: extra coverage is not supported by the kernel 2019/11/01 18:42:37 setuid sandbox: enabled 2019/11/01 18:42:37 namespace sandbox: enabled 2019/11/01 18:42:37 Android sandbox: /sys/fs/selinux/policy does not exist 2019/11/01 18:42:37 fault injection: enabled 2019/11/01 18:42:37 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2019/11/01 18:42:37 net packet injection: enabled 2019/11/01 18:42:37 net device setup: enabled 2019/11/01 18:42:37 concurrency sanitizer: enabled 2019/11/01 18:42:43 adding functions to KCSAN blacklist: '__nf_ct_refresh_acct' 'blk_mq_get_request' 'do_nanosleep' 'pid_update_inode' 'tomoyo_supervisor' 'tick_do_update_jiffies64' 'ep_poll' 'tick_sched_do_timer' '__hrtimer_run_queues' 'tcp_add_backlog' 'task_dump_owner' 'blk_mq_run_hw_queue' 'update_defense_level' 'ext4_free_inodes_count' '__nf_conntrack_find_get' 'generic_permission' 'ktime_get_real_seconds' 'find_get_pages_range_tag' 'rcu_gp_fqs_check_wake' 'find_next_bit' 'common_perm_cond' 'run_timer_softirq' 'ext4_free_inode' 'pipe_poll' 'tcp_poll' syzkaller login: [ 65.256889][ T7212] ================================================================== [ 65.265019][ T7212] BUG: KCSAN: data-race in mod_timer / timer_clear_idle [ 65.271929][ T7212] [ 65.274245][ T7212] write to 0xffff88812be1b6e4 of 1 bytes by task 0 on cpu 0: [ 65.281601][ T7212] timer_clear_idle+0x42/0x50 [ 65.286274][ T7212] __tick_nohz_idle_restart_tick+0x36/0x1b0 [ 65.292153][ T7212] tick_nohz_idle_exit+0x1af/0x1e0 [ 65.297250][ T7212] do_idle+0xb1/0x280 [ 65.301216][ T7212] cpu_startup_entry+0x1b/0x20 [ 65.305962][ T7212] rest_init+0xec/0xf6 [ 65.310015][ T7212] arch_call_rest_init+0x17/0x37 [ 65.314932][ T7212] start_kernel+0x838/0x85e [ 65.319431][ T7212] x86_64_start_reservations+0x29/0x2b [ 65.324869][ T7212] x86_64_start_kernel+0x72/0x76 [ 65.329796][ T7212] secondary_startup_64+0xa4/0xb0 [ 65.334793][ T7212] [ 65.337106][ T7212] read to 0xffff88812be1b6e4 of 1 bytes by task 7212 on cpu 1: [ 65.344633][ T7212] mod_timer+0x50d/0x7a0 [ 65.348860][ T7212] sk_reset_timer+0x2d/0x70 [ 65.353350][ T7212] tcp_rearm_rto.part.0+0x190/0x240 [ 65.358529][ T7212] tcp_rearm_rto+0x4f/0x60 [ 65.362927][ T7212] tcp_event_new_data_sent+0x1bb/0x1c0 [ 65.368370][ T7212] tcp_write_xmit+0xa16/0x3080 [ 65.373122][ T7212] __tcp_push_pending_frames+0x7b/0x1d0 [ 65.378651][ T7212] tcp_push+0x1e9/0x3d0 [ 65.382795][ T7212] tcp_sendmsg_locked+0x1d1e/0x1f30 [ 65.387975][ T7212] tcp_sendmsg+0x39/0x60 [ 65.392213][ T7212] inet_sendmsg+0x6d/0x90 [ 65.396554][ T7212] sock_sendmsg+0x9f/0xc0 [ 65.401308][ T7212] sock_write_iter+0x16b/0x210 [ 65.406046][ T7212] [ 65.408358][ T7212] Reported by Kernel Concurrency Sanitizer on: [ 65.414497][ T7212] CPU: 1 PID: 7212 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 65.421931][ T7212] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.431965][ T7212] ================================================================== [ 65.440006][ T7212] Kernel panic - not syncing: panic_on_warn set ... [ 65.446578][ T7212] CPU: 1 PID: 7212 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0 [ 65.454024][ T7212] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.464064][ T7212] Call Trace: [ 65.467346][ T7212] dump_stack+0xf5/0x159 [ 65.471575][ T7212] panic+0x210/0x640 [ 65.475460][ T7212] ? tcp_sendmsg_locked+0x1d1e/0x1f30 [ 65.480919][ T7212] ? vprintk_func+0x8d/0x140 [ 65.485499][ T7212] kcsan_report.cold+0xc/0x10 [ 65.490175][ T7212] __kcsan_setup_watchpoint+0x32e/0x4a0 [ 65.495704][ T7212] __tsan_read1+0x2c/0x30 [ 65.500022][ T7212] mod_timer+0x50d/0x7a0 [ 65.504253][ T7212] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 65.509873][ T7212] ? __kcsan_setup_watchpoint+0x6b/0x4a0 [ 65.515495][ T7212] sk_reset_timer+0x2d/0x70 [ 65.519991][ T7212] tcp_rearm_rto.part.0+0x190/0x240 [ 65.525185][ T7212] tcp_rearm_rto+0x4f/0x60 [ 65.529588][ T7212] tcp_event_new_data_sent+0x1bb/0x1c0 [ 65.535033][ T7212] tcp_write_xmit+0xa16/0x3080 [ 65.539794][ T7212] ? kmem_cache_alloc_node_trace+0x273/0x670 [ 65.545767][ T7212] __tcp_push_pending_frames+0x7b/0x1d0 [ 65.551300][ T7212] tcp_push+0x1e9/0x3d0 [ 65.555465][ T7212] tcp_sendmsg_locked+0x1d1e/0x1f30 [ 65.560664][ T7212] tcp_sendmsg+0x39/0x60 [ 65.564904][ T7212] inet_sendmsg+0x6d/0x90 [ 65.569221][ T7212] ? inet_send_prepare+0x200/0x200 [ 65.575274][ T7212] sock_sendmsg+0x9f/0xc0 [ 65.579595][ T7212] sock_write_iter+0x16b/0x210 [ 65.584351][ T7212] new_sync_write+0x388/0x4a0 [ 65.589018][ T7212] __vfs_write+0xb1/0xc0 [ 65.593277][ T7212] vfs_write+0x18a/0x390 [ 65.597508][ T7212] ksys_write+0xd5/0x1b0 [ 65.601752][ T7212] __x64_sys_write+0x4c/0x60 [ 65.606330][ T7212] do_syscall_64+0xcc/0x370 [ 65.610825][ T7212] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 65.616700][ T7212] RIP: 0033:0x47c530 [ 65.620603][ T7212] Code: 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 49 c7 c2 00 00 00 00 49 c7 c0 00 00 00 00 49 c7 c1 00 00 00 00 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 30 [ 65.640192][ T7212] RSP: 002b:000000c420f3b4f8 EFLAGS: 00000216 ORIG_RAX: 0000000000000001 [ 65.648587][ T7212] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530 [ 65.656553][ T7212] RDX: 0000000000000008 RSI: 000000c420164020 RDI: 0000000000000003 [ 65.664523][ T7212] RBP: 000000c420f3b550 R08: 0000000000000000 R09: 0000000000000000 [ 65.672483][ T7212] R10: 0000000000000000 R11: 0000000000000216 R12: 000000c4200c3b00 [ 65.680442][ T7212] R13: 0000000000000007 R14: 0000000000c1d600 R15: 0000000000001fd3 [ 66.813978][ T7212] Shutting down cpus with NMI [ 66.820150][ T7212] Kernel Offset: disabled [ 66.824560][ T7212] Rebooting in 86400 seconds..