[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[ 34.978419][ T26] audit: type=1800 audit(1571841305.835:25): pid=7093 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0
[ 35.012697][ T26] audit: type=1800 audit(1571841305.835:26): pid=7093 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0
[ 35.043245][ T26] audit: type=1800 audit(1571841305.835:27): pid=7093 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[1G[[32m ok [39;49m8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
Debian GNU/Linux 7 syzkaller ttyS0
Warning: Permanently added '10.128.0.116' (ECDSA) to the list of known hosts.
2019/10/23 14:35:16 fuzzer started
2019/10/23 14:35:17 dialing manager at 10.128.0.105:40369
2019/10/23 14:35:17 syscalls: 2524
2019/10/23 14:35:17 code coverage: enabled
2019/10/23 14:35:17 comparison tracing: enabled
2019/10/23 14:35:17 extra coverage: extra coverage is not supported by the kernel
2019/10/23 14:35:17 setuid sandbox: enabled
2019/10/23 14:35:17 namespace sandbox: enabled
2019/10/23 14:35:17 Android sandbox: /sys/fs/selinux/policy does not exist
2019/10/23 14:35:17 fault injection: enabled
2019/10/23 14:35:17 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled
2019/10/23 14:35:17 net packet injection: enabled
2019/10/23 14:35:17 net device setup: enabled
2019/10/23 14:35:17 concurrency sanitizer: enabled
2019/10/23 14:35:23 adding functions to KCSAN blacklist: 'find_get_pages_range_tag' 'blk_mq_get_request' 'generic_write_end' '__nf_ct_refresh_acct' 'wbt_issue' 'taskstats_exit' 'tcp_poll' 'ext4_free_inode' 'fanotify_handle_event' 'generic_fillattr' 'tcp_add_backlog' 'ep_poll' 'pcpu_alloc' 'tick_do_update_jiffies64' 'pipe_poll' 'find_next_bit' 'ext4_has_free_clusters' 'vti_tunnel_xmit' 'tomoyo_supervisor' 'generic_permission' 'ktime_get_real_seconds' '__nf_conntrack_find_get' 'echo_char' 'ext4_nonda_switch' '__splice_from_pipe' '__hrtimer_run_queues' 'common_perm_cond' 'add_timer' 'tick_nohz_idle_stop_tick' 'page_counter_try_charge'
syzkaller login: [ 61.308707][ C0] ==================================================================
[ 61.316978][ C0] BUG: KCSAN: data-race in tick_sched_do_timer / tick_sched_do_timer
[ 61.325048][ C0]
[ 61.327386][ C0] read to 0xffffffff85cb2790 of 4 bytes by interrupt on cpu 1:
[ 61.334938][ C0] tick_sched_do_timer+0x33/0xe0
[ 61.339888][ C0] tick_sched_timer+0x43/0xe0
[ 61.344732][ C0] __hrtimer_run_queues+0x288/0x600
[ 61.349932][ C0] hrtimer_interrupt+0x22a/0x480
[ 61.354950][ C0] smp_apic_timer_interrupt+0xdc/0x280
[ 61.360410][ C0] apic_timer_interrupt+0xf/0x20
[ 61.365380][ C0] __kcsan_check_watchpoint+0x66/0x180
[ 61.370948][ C0] __tsan_read8+0x15/0x30
[ 61.375281][ C0] ipt_do_table+0x8e/0xe60
[ 61.379704][ C0] iptable_filter_hook+0x4a/0x60
[ 61.384788][ C0] nf_hook_slow+0x83/0x160
[ 61.389201][ C0] ip_local_deliver+0x1e5/0x210
[ 61.394360][ C0] ip_rcv_finish+0x121/0x160
[ 61.399040][ C0] ip_rcv+0x18f/0x1a0
[ 61.403017][ C0]
[ 61.405346][ C0] write to 0xffffffff85cb2790 of 4 bytes by interrupt on cpu 0:
[ 61.412984][ C0] tick_sched_do_timer+0xc0/0xe0
[ 61.418019][ C0] tick_sched_timer+0x43/0xe0
[ 61.422700][ C0] __hrtimer_run_queues+0x288/0x600
[ 61.427915][ C0] hrtimer_interrupt+0x22a/0x480
[ 61.432851][ C0] smp_apic_timer_interrupt+0xdc/0x280
[ 61.438322][ C0] apic_timer_interrupt+0xf/0x20
[ 61.443378][ C0] _copy_to_iter+0x1e6/0xa20
[ 61.447971][ C0] simple_copy_to_iter+0x3f/0x60
[ 61.452906][ C0] __skb_datagram_iter+0x23b/0x460
[ 61.458022][ C0] skb_copy_datagram_iter+0x66/0x170
[ 61.463322][ C0] tcp_recvmsg+0x106c/0x1a30
[ 61.467911][ C0] inet_recvmsg+0xbb/0x250
[ 61.472327][ C0] sock_recvmsg+0x92/0xb0
[ 61.476664][ C0]
[ 61.478986][ C0] Reported by Kernel Concurrency Sanitizer on:
[ 61.485870][ C0] CPU: 0 PID: 7255 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0
[ 61.493304][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 61.503793][ C0] ==================================================================
[ 61.511841][ C0] Kernel panic - not syncing: panic_on_warn set ...
[ 61.518957][ C0] CPU: 0 PID: 7255 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0
[ 61.527571][ C0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 61.537847][ C0] Call Trace:
[ 61.541197][ C0]
[ 61.544144][ C0] dump_stack+0xf5/0x159
[ 61.548643][ C0] panic+0x210/0x640
[ 61.552526][ C0] ? __skb_datagram_iter+0x23b/0x460
[ 61.557803][ C0] ? vprintk_func+0x8d/0x140
[ 61.562378][ C0] kcsan_report.cold+0xc/0x10
[ 61.567051][ C0] __kcsan_setup_watchpoint+0x32e/0x4a0
[ 61.572612][ C0] __tsan_write4+0x32/0x40
[ 61.577018][ C0] tick_sched_do_timer+0xc0/0xe0
[ 61.581955][ C0] tick_sched_timer+0x43/0xe0
[ 61.586612][ C0] __hrtimer_run_queues+0x288/0x600
[ 61.591883][ C0] ? tick_sched_do_timer+0xe0/0xe0
[ 61.596981][ C0] hrtimer_interrupt+0x22a/0x480
[ 61.601910][ C0] smp_apic_timer_interrupt+0xdc/0x280
[ 61.607343][ C0] ? do_IRQ+0xcb/0x180
[ 61.611390][ C0] apic_timer_interrupt+0xf/0x20
[ 61.616298][ C0]
[ 61.619229][ C0] RIP: 0010:_copy_to_iter+0x1e6/0xa20
[ 61.625548][ C0] Code: 89 df 4c 89 e6 e8 9a 96 f8 fe 4c 39 e3 75 0b e8 70 95 f8 fe 49 83 c5 10 31 db e8 65 95 f8 fe 4d 8d 47 20 4c 89 c7 4c 89 45 b0 75 94 05 ff 4c 89 f7 4d 8b 67 20 e8 69 94 05 ff 4c 89 e8 49 2b
[ 61.645224][ C0] RSP: 0018:ffffc9000188b950 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
[ 61.653614][ C0] RAX: ffff888126f24100 RBX: 00000000000004ee RCX: ffffffff824d3266
[ 61.661563][ C0] RDX: 0000000000000000 RSI: ffffffff824d327b RDI: ffffc9000188bcf0
[ 61.669511][ C0] RBP: ffffc9000188b9f8 R08: ffffc9000188bcf0 R09: 0000c9000188bd77
[ 61.677458][ C0] R10: 00000000aaaaaaab R11: ffffffff86045c70 R12: 0000000000001000
[ 61.685407][ C0] R13: ffffc9000188bd68 R14: ffffc9000188bce8 R15: ffffc9000188bcd0
[ 61.693384][ C0] ? _copy_to_iter+0x1c6/0xa20
[ 61.698126][ C0] ? _copy_to_iter+0x1db/0xa20
[ 61.703665][ C0] ? __tsan_read8+0x2c/0x30
[ 61.708163][ C0] simple_copy_to_iter+0x3f/0x60
[ 61.713237][ C0] __skb_datagram_iter+0x23b/0x460
[ 61.718347][ C0] ? skb_copy_datagram_iter+0x170/0x170
[ 61.723875][ C0] skb_copy_datagram_iter+0x66/0x170
[ 61.729145][ C0] tcp_recvmsg+0x106c/0x1a30
[ 61.733720][ C0] ? __kcsan_setup_watchpoint+0x6b/0x4a0
[ 61.739336][ C0] ? __kcsan_setup_watchpoint+0x6b/0x4a0
[ 61.744946][ C0] inet_recvmsg+0xbb/0x250
[ 61.749346][ C0] ? __tsan_read8+0x2c/0x30
[ 61.753827][ C0] ? inet_sendpage+0x100/0x100
[ 61.758568][ C0] sock_recvmsg+0x92/0xb0
[ 61.762872][ C0] sock_read_iter+0x15f/0x1e0
[ 61.767526][ C0] new_sync_read+0x389/0x4f0
[ 61.772115][ C0] __vfs_read+0xb1/0xc0
[ 61.776262][ C0] vfs_read+0x143/0x2c0
[ 61.780401][ C0] ksys_read+0xd5/0x1b0
[ 61.784534][ C0] __x64_sys_read+0x4c/0x60
[ 61.789024][ C0] do_syscall_64+0xcc/0x370
[ 61.793504][ C0] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 61.799368][ C0] RIP: 0033:0x47c530
[ 61.803244][ C0] 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
[ 61.822821][ C0] RSP: 002b:000000c4203a37d8 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
[ 61.831207][ C0] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000047c530
[ 61.839422][ C0] RDX: 0000000000001000 RSI: 000000c420054000 RDI: 0000000000000003
[ 61.847376][ C0] RBP: 000000c4203a3830 R08: 0000000000000000 R09: 0000000000000000
[ 61.855325][ C0] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000200
[ 61.863278][ C0] R13: ffffffffffffffff R14: 0000000000000002 R15: ffffffffffffffff
[ 61.872562][ C0] Kernel Offset: disabled
[ 61.876908][ C0] Rebooting in 86400 seconds..