[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.183' (ECDSA) to the list of known hosts. 2021/01/16 00:58:30 fuzzer started 2021/01/16 00:58:30 dialing manager at 10.128.0.105:36185 2021/01/16 00:58:31 syscalls: 3465 2021/01/16 00:58:31 code coverage: enabled 2021/01/16 00:58:31 comparison tracing: enabled 2021/01/16 00:58:31 extra coverage: enabled 2021/01/16 00:58:31 setuid sandbox: enabled 2021/01/16 00:58:31 namespace sandbox: enabled 2021/01/16 00:58:31 Android sandbox: /sys/fs/selinux/policy does not exist 2021/01/16 00:58:31 fault injection: enabled 2021/01/16 00:58:31 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2021/01/16 00:58:31 net packet injection: enabled 2021/01/16 00:58:31 net device setup: enabled 2021/01/16 00:58:31 concurrency sanitizer: enabled 2021/01/16 00:58:31 devlink PCI setup: PCI device 0000:00:10.0 is not available 2021/01/16 00:58:31 USB emulation: enabled 2021/01/16 00:58:31 hci packet injection: enabled 2021/01/16 00:58:31 wifi device emulation: enabled 2021/01/16 00:58:34 suppressing KCSAN reports in functions: '__send_signal' 'complete_signal' 'ext4_free_inode' 'n_tty_receive_buf_common' '__filemap_fdatawrite_range' 'filemap_map_pages' 'do_signal_stop' '__blk_mq_sched_dispatch_requests' 'exit_mm' 'xas_clear_mark' 'pcpu_alloc' 'ext4_writepages' 'tick_nohz_next_event' 'ext4_free_inodes_count' 'isolate_migratepages_block' 'ext4_write_end' 'shmem_add_to_page_cache' 'xas_find_marked' 'wbt_issue' 'find_get_pages_range_tag' 'do_select' 'wbt_done' 'tick_sched_timer' 'step_into' 'expire_timers' 'do_sys_poll' '_prb_read_valid' 'kauditd_thread' '__xa_clear_mark' 'blk_mq_rq_ctx_init' 'do_epoll_ctl' 'bpf_lru_pop_free' 'futex_wait_queue_me' 'ext4_mark_iloc_dirty' 'lookup_fast' 'audit_log_start' 'direct_page_fault' 'generic_write_end' 'alloc_pid' '__delete_from_page_cache' 'blk_mq_dispatch_rq_list' '__io_cqring_fill_event' '__add_to_page_cache_locked' 'do_nanosleep' 'generic_file_buffered_read' 'ext4_mb_regular_allocator' '__ext4_new_inode' '__mark_inode_dirty' 'dst_cache_set_ip6' 'blk_mq_sched_dispatch_requests' 'dd_has_work' 'delete_from_page_cache_batch' '__find_get_block' 2021/01/16 00:58:34 fetching corpus: 0, signal 0/2000 (executing program) 2021/01/16 00:58:34 fetching corpus: 50, signal 21359/25251 (executing program) 2021/01/16 00:58:35 fetching corpus: 100, signal 32008/37767 (executing program) 2021/01/16 00:58:35 fetching corpus: 150, signal 46002/53540 (executing program) 2021/01/16 00:58:35 fetching corpus: 200, signal 57351/66669 (executing program) 2021/01/16 00:58:35 fetching corpus: 250, signal 63831/74905 (executing program) 2021/01/16 00:58:35 fetching corpus: 300, signal 70398/83190 (executing program) 2021/01/16 00:58:35 fetching corpus: 350, signal 78965/93422 (executing program) 2021/01/16 00:58:36 fetching corpus: 400, signal 84914/101065 (executing program) 2021/01/16 00:58:36 fetching corpus: 450, signal 89748/107544 (executing program) 2021/01/16 00:58:36 fetching corpus: 500, signal 93769/113240 (executing program) 2021/01/16 00:58:36 fetching corpus: 550, signal 100346/121373 (executing program) 2021/01/16 00:58:36 fetching corpus: 600, signal 104580/127242 (executing program) 2021/01/16 00:58:36 fetching corpus: 650, signal 108227/132512 (executing program) 2021/01/16 00:58:36 fetching corpus: 700, signal 112618/138469 (executing program) 2021/01/16 00:58:36 fetching corpus: 750, signal 119295/146602 (executing program) 2021/01/16 00:58:37 fetching corpus: 800, signal 122894/151769 (executing program) 2021/01/16 00:58:37 fetching corpus: 850, signal 125912/156346 (executing program) 2021/01/16 00:58:38 fetching corpus: 900, signal 129254/161204 (executing program) 2021/01/16 00:58:38 fetching corpus: 950, signal 132312/165787 (executing program) 2021/01/16 00:58:38 fetching corpus: 1000, signal 138022/172892 (executing program) 2021/01/16 00:58:38 fetching corpus: 1050, signal 140763/177229 (executing program) 2021/01/16 00:58:38 fetching corpus: 1100, signal 143832/181816 (executing program) 2021/01/16 00:58:38 fetching corpus: 1150, signal 146884/186350 (executing program) 2021/01/16 00:58:39 fetching corpus: 1200, signal 149413/190391 (executing program) 2021/01/16 00:58:39 fetching corpus: 1250, signal 151443/193938 (executing program) 2021/01/16 00:58:39 fetching corpus: 1300, signal 153469/197432 (executing program) syzkaller login: [ 40.104919][ T0] ================================================================== [ 40.113145][ T0] BUG: KCSAN: data-race in tick_nohz_stop_tick / tick_nohz_stop_tick [ 40.121202][ T0] [ 40.123520][ T0] write to 0xffffffff86fc2460 of 4 bytes by task 0 on cpu 1: [ 40.130899][ T0] tick_nohz_stop_tick+0x99/0x410 [ 40.135915][ T0] tick_nohz_idle_stop_tick+0x148/0x2e0 [ 40.141449][ T0] do_idle+0x176/0x230 [ 40.145485][ T0] cpu_startup_entry+0x15/0x20 [ 40.150227][ T0] secondary_startup_64_no_verify+0xb0/0xbb [ 40.156091][ T0] [ 40.158390][ T0] read to 0xffffffff86fc2460 of 4 bytes by task 0 on cpu 0: [ 40.165651][ T0] tick_nohz_stop_tick+0x73/0x410 [ 40.170753][ T0] tick_nohz_idle_stop_tick+0x148/0x2e0 [ 40.176269][ T0] do_idle+0x176/0x230 [ 40.180300][ T0] cpu_startup_entry+0x15/0x20 [ 40.185029][ T0] rest_init+0xd7/0xe0 [ 40.189080][ T0] arch_call_rest_init+0xa/0xb [ 40.193820][ T0] start_kernel+0x59b/0x620 [ 40.198305][ T0] secondary_startup_64_no_verify+0xb0/0xbb [ 40.204258][ T0] [ 40.206670][ T0] Reported by Kernel Concurrency Sanitizer on: [ 40.212798][ T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.11.0-rc3-syzkaller #0 [ 40.220741][ T0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.230764][ T0] ================================================================== [ 40.238788][ T0] Kernel panic - not syncing: panic_on_warn set ... [ 40.245342][ T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.11.0-rc3-syzkaller #0 [ 40.253314][ T0] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.263338][ T0] Call Trace: [ 40.266589][ T0] dump_stack+0x116/0x15d [ 40.270936][ T0] panic+0x1e7/0x5fa [ 40.274801][ T0] ? vprintk_emit+0x2e2/0x360 [ 40.279448][ T0] kcsan_report+0x67b/0x680 [ 40.283943][ T0] ? kcsan_setup_watchpoint+0x47b/0x4e0 [ 40.289465][ T0] ? tick_nohz_stop_tick+0x73/0x410 [ 40.294730][ T0] ? tick_nohz_idle_stop_tick+0x148/0x2e0 [ 40.300433][ T0] ? do_idle+0x176/0x230 [ 40.304662][ T0] ? cpu_startup_entry+0x15/0x20 [ 40.309581][ T0] ? rest_init+0xd7/0xe0 [ 40.313794][ T0] ? arch_call_rest_init+0xa/0xb [ 40.318803][ T0] ? start_kernel+0x59b/0x620 [ 40.323454][ T0] ? secondary_startup_64_no_verify+0xb0/0xbb [ 40.329494][ T0] ? hrtimer_next_event_without+0x3d6/0x3f0 [ 40.335361][ T0] ? tick_nohz_next_event+0x2c7/0x300 [ 40.340707][ T0] kcsan_setup_watchpoint+0x47b/0x4e0 [ 40.346053][ T0] tick_nohz_stop_tick+0x73/0x410 [ 40.351065][ T0] tick_nohz_idle_stop_tick+0x148/0x2e0 [ 40.356588][ T0] do_idle+0x176/0x230 [ 40.360628][ T0] cpu_startup_entry+0x15/0x20 [ 40.365361][ T0] rest_init+0xd7/0xe0 [ 40.369416][ T0] ? time_init+0xc/0xc [ 40.373457][ T0] arch_call_rest_init+0xa/0xb [ 40.378286][ T0] start_kernel+0x59b/0x620 [ 40.382779][ T0] secondary_startup_64_no_verify+0xb0/0xbb [ 40.389473][ T0] Kernel Offset: disabled [ 40.393779][ T0] Rebooting in 86400 seconds..