[ OK ] Started OpenBSD Secure Shell server. [ 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 '10.128.1.73' (ECDSA) to the list of known hosts. 2021/04/26 10:24:39 fuzzer started 2021/04/26 10:24:40 dialing manager at 10.128.0.163:45705 2021/04/26 10:25:09 syscalls: 1982 2021/04/26 10:25:09 code coverage: enabled 2021/04/26 10:25:09 comparison tracing: enabled 2021/04/26 10:25:09 extra coverage: enabled 2021/04/26 10:25:09 setuid sandbox: enabled 2021/04/26 10:25:09 namespace sandbox: enabled 2021/04/26 10:25:09 Android sandbox: enabled 2021/04/26 10:25:09 fault injection: enabled 2021/04/26 10:25:09 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2021/04/26 10:25:09 net packet injection: /dev/net/tun does not exist 2021/04/26 10:25:09 net device setup: enabled 2021/04/26 10:25:09 concurrency sanitizer: enabled 2021/04/26 10:25:09 devlink PCI setup: PCI device 0000:00:10.0 is not available 2021/04/26 10:25:09 USB emulation: /dev/raw-gadget does not exist 2021/04/26 10:25:09 hci packet injection: /dev/vhci does not exist 2021/04/26 10:25:09 wifi device emulation: /sys/class/mac80211_hwsim/ does not exist 2021/04/26 10:25:09 802.15.4 emulation: /sys/bus/platform/devices/mac802154_hwsim does not exist 2021/04/26 10:25:11 suppressing KCSAN reports in functions: 'blk_mq_rq_ctx_init' 'do_signal_stop' 'do_nanosleep' 'next_uptodate_page' 'dd_has_work' 'n_tty_receive_char_special' 'lookup_fast' 'ext4_writepages' 'shmem_file_read_iter' 'internal_add_timer' 'ext4_mark_iloc_dirty' 'generic_write_end' 'step_into' 'ext4_free_inodes_count' 'expire_timers' '__send_signal' 'ext4_es_lookup_extent' 'blk_mq_dispatch_rq_list' 'n_tty_receive_buf_common' 'do_group_exit' 'ns_capable' 'aio_read_events' '__xa_clear_mark' 'ext4_free_inode' 'fast_dput' 'kauditd_thread' '__add_to_page_cache_locked' 'put_pipe_info' 'lo_ioctl' 'xas_find_marked' 'xas_clear_mark' 'do_readlinkat' 'shmem_symlink' 'do_select' '__blkdev_get' '__find_get_block' 'exit_mm' 'blk_mq_sched_dispatch_requests' 'shmem_mknod' 'alloc_pid' 'do_sys_poll' 'ext4_set_iomap' '__mark_inode_dirty' 'complete_signal' 'tick_nohz_next_event' '__ext4_new_inode' 'audit_log_start' 2021/04/26 10:25:11 fetching corpus: 0, signal 0/2000 (executing program) 2021/04/26 10:25:11 fetching corpus: 50, signal 12759/16583 (executing program) 2021/04/26 10:25:11 fetching corpus: 100, signal 23343/28851 (executing program) 2021/04/26 10:25:11 fetching corpus: 150, signal 30686/37818 (executing program) 2021/04/26 10:25:11 fetching corpus: 200, signal 35557/44267 (executing program) 2021/04/26 10:25:11 fetching corpus: 250, signal 38524/48846 (executing program) 2021/04/26 10:25:11 fetching corpus: 300, signal 43414/55251 (executing program) syzkaller login: [ 48.886885][ T1738] ================================================================== [ 48.888288][ T1738] BUG: KCSAN: data-race in futex_wait_queue_me / prepare_signal [ 48.889425][ T1738] [ 48.889769][ T1738] write to 0xffff888100c6006c of 4 bytes by task 1739 on cpu 1: [ 48.890831][ T1738] futex_wait_queue_me+0x198/0x260 [ 48.891626][ T1738] futex_wait+0x143/0x430 [ 48.892250][ T1738] do_futex+0x9e8/0x1e10 [ 48.892914][ T1738] __se_sys_futex+0x2a8/0x390 [ 48.893691][ T1738] __x64_sys_futex+0x74/0x80 [ 48.894381][ T1738] do_syscall_64+0x34/0x50 [ 48.895098][ T1738] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 48.895936][ T1738] [ 48.896326][ T1738] read to 0xffff888100c6006c of 4 bytes by task 1738 on cpu 0: [ 48.897428][ T1738] prepare_signal+0x872/0xd80 [ 48.898126][ T1738] __send_signal+0x64/0x760 [ 48.898837][ T1738] send_signal+0x38e/0x3d0 [ 48.899544][ T1738] do_send_specific+0x13d/0x1c0 [ 48.900267][ T1738] __x64_sys_tgkill+0x108/0x140 [ 48.900949][ T1738] do_syscall_64+0x34/0x50 [ 48.901549][ T1738] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 48.902342][ T1738] [ 48.902665][ T1738] Reported by Kernel Concurrency Sanitizer on: [ 48.903699][ T1738] CPU: 0 PID: 1738 Comm: syz-fuzzer Not tainted 5.12.0-syzkaller #0 [ 48.905101][ T1738] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.906599][ T1738] ================================================================== 2021/04/26 10:25:11 fetching corpus: 350, signal 47902/61174 (executing program) 2021/04/26 10:25:11 fetching corpus: 400, signal 51474/66186 (executing program) 2021/04/26 10:25:11 fetching corpus: 450, signal 54306/70442 (executing program) 2021/04/26 10:25:11 fetching corpus: 500, signal 56947/74490 (executing program) 2021/04/26 10:25:11 fetching corpus: 550, signal 59103/78063 (executing program) 2021/04/26 10:25:11 fetching corpus: 600, signal 61522/81776 (executing program) 2021/04/26 10:25:11 fetching corpus: 650, signal 64262/85763 (executing program) 2021/04/26 10:25:11 fetching corpus: 700, signal 65901/88753 (executing program) 2021/04/26 10:25:11 fetching corpus: 750, signal 68199/92309 (executing program) 2021/04/26 10:25:11 fetching corpus: 800, signal 70178/95569 (executing program) 2021/04/26 10:25:12 fetching corpus: 850, 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