[ 45.707871] audit: type=1800 audit(1579546477.940:29): pid=8042 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 45.741967] audit: type=1800 audit(1579546477.940:30): pid=8042 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?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 '10.128.0.166' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 55.319190] kauditd_printk_skb: 5 callbacks suppressed [ 55.319210] audit: type=1400 audit(1579546487.550:36): avc: denied { map } for pid=8228 comm="syz-executor166" path="/root/syz-executor166599771" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 executing program [ 55.413906] ================================================================== [ 55.413946] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 55.413958] Write of size 8 at addr ffff88808ffbcec8 by task syz-executor166/8240 [ 55.413961] [ 55.413976] CPU: 0 PID: 8240 Comm: syz-executor166 Not tainted 4.19.97-syzkaller #0 [ 55.413984] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.413989] Call Trace: [ 55.414006] dump_stack+0x197/0x210 [ 55.414025] ? con_shutdown+0x85/0x90 [ 55.414044] print_address_description.cold+0x7c/0x20d [ 55.414061] ? con_shutdown+0x85/0x90 [ 55.414077] kasan_report.cold+0x8c/0x2ba [ 55.414094] ? set_palette+0x1c0/0x1c0 [ 55.414113] __asan_report_store8_noabort+0x17/0x20 [ 55.414127] con_shutdown+0x85/0x90 [ 55.414142] release_tty+0xe4/0x4d0 [ 55.414159] tty_release_struct+0x3c/0x50 [ 55.414174] tty_release+0xbcb/0xe90 [ 55.414197] ? tty_release_struct+0x50/0x50 [ 55.414213] __fput+0x2dd/0x8b0 [ 55.414234] ____fput+0x16/0x20 [ 55.414250] task_work_run+0x145/0x1c0 [ 55.414270] do_exit+0xc1f/0x30d0 [ 55.414295] ? mm_update_next_owner+0x660/0x660 [ 55.414310] ? up_read+0x1a/0x110 [ 55.414323] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.414337] ? __do_page_fault+0x484/0xe90 [ 55.414358] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.414373] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.414390] do_group_exit+0x135/0x370 [ 55.414410] __x64_sys_exit_group+0x44/0x50 [ 55.414427] do_syscall_64+0xfd/0x620 [ 55.414447] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.414458] RIP: 0033:0x43ff78 [ 55.414470] Code: Bad RIP value. [ 55.414479] RSP: 002b:00007ffed0785788 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 55.414493] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff78 [ 55.414509] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 55.414518] RBP: 00000000004bf990 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 55.414527] R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001 [ 55.414535] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 55.414554] [ 55.414560] Allocated by task 8240: [ 55.414574] save_stack+0x45/0xd0 [ 55.414586] kasan_kmalloc+0xce/0xf0 [ 55.414598] kmem_cache_alloc_trace+0x152/0x760 [ 55.414612] vc_allocate+0x1f5/0x760 [ 55.414625] con_install+0x52/0x410 [ 55.414644] tty_init_dev+0xf7/0x460 [ 55.414656] tty_open+0x4bf/0xb70 [ 55.414668] chrdev_open+0x245/0x6b0 [ 55.414678] do_dentry_open+0x4c3/0x1210 [ 55.414689] vfs_open+0xa0/0xd0 [ 55.414701] path_openat+0x10d7/0x45e0 [ 55.414710] do_filp_open+0x1a1/0x280 [ 55.414721] do_sys_open+0x3fe/0x550 [ 55.414733] __x64_sys_open+0x7e/0xc0 [ 55.414746] do_syscall_64+0xfd/0x620 [ 55.414758] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.414762] [ 55.414768] Freed by task 8237: [ 55.414780] save_stack+0x45/0xd0 [ 55.414794] __kasan_slab_free+0x102/0x150 [ 55.414807] kasan_slab_free+0xe/0x10 [ 55.414818] kfree+0xcf/0x220 [ 55.414828] vt_disallocate_all+0x2bd/0x3e0 [ 55.414837] vt_ioctl+0xc38/0x2530 [ 55.414848] tty_ioctl+0x7f3/0x1510 [ 55.414859] do_vfs_ioctl+0xd5f/0x1380 [ 55.414869] ksys_ioctl+0xab/0xd0 [ 55.414880] __x64_sys_ioctl+0x73/0xb0 [ 55.414894] do_syscall_64+0xfd/0x620 [ 55.414907] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.414910] [ 55.414920] The buggy address belongs to the object at ffff88808ffbcdc0 [ 55.414920] which belongs to the cache kmalloc-2048 of size 2048 [ 55.414932] The buggy address is located 264 bytes inside of [ 55.414932] 2048-byte region [ffff88808ffbcdc0, ffff88808ffbd5c0) [ 55.414936] The buggy address belongs to the page: [ 55.414949] page:ffffea00023fef00 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 [ 55.414962] flags: 0xfffe0000008100(slab|head) [ 55.414980] raw: 00fffe0000008100 ffffea00023eac08 ffffea00024fc288 ffff88812c31cc40 [ 55.414996] raw: 0000000000000000 ffff88808ffbc540 0000000100000003 0000000000000000 [ 55.415002] page dumped because: kasan: bad access detected [ 55.415005] [ 55.415009] Memory state around the buggy address: [ 55.415020] ffff88808ffbcd80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 55.415031] ffff88808ffbce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.415041] >ffff88808ffbce80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.415047] ^ [ 55.415057] ffff88808ffbcf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.415068] ffff88808ffbcf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.415073] ================================================================== [ 55.415078] Disabling lock debugging due to kernel taint [ 55.415085] Kernel panic - not syncing: panic_on_warn set ... [ 55.415085] [ 55.415098] CPU: 0 PID: 8240 Comm: syz-executor166 Tainted: G B 4.19.97-syzkaller #0 [ 55.415105] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.415109] Call Trace: [ 55.415124] dump_stack+0x197/0x210 [ 55.415138] ? con_shutdown+0x85/0x90 [ 55.415149] panic+0x26a/0x50e [ 55.415160] ? __warn_printk+0xf3/0xf3 [ 55.415176] ? lock_downgrade+0x880/0x880 [ 55.415193] ? trace_hardirqs_on+0x67/0x220 [ 55.415206] ? trace_hardirqs_on+0x5e/0x220 [ 55.415223] ? con_shutdown+0x85/0x90 [ 55.415237] kasan_end_report+0x47/0x4f [ 55.415251] kasan_report.cold+0xa9/0x2ba [ 55.415266] ? set_palette+0x1c0/0x1c0 [ 55.415282] __asan_report_store8_noabort+0x17/0x20 [ 55.415296] con_shutdown+0x85/0x90 [ 55.415310] release_tty+0xe4/0x4d0 [ 55.415324] tty_release_struct+0x3c/0x50 [ 55.415338] tty_release+0xbcb/0xe90 [ 55.415356] ? tty_release_struct+0x50/0x50 [ 55.415369] __fput+0x2dd/0x8b0 [ 55.415386] ____fput+0x16/0x20 [ 55.415397] task_work_run+0x145/0x1c0 [ 55.415410] do_exit+0xc1f/0x30d0 [ 55.415427] ? mm_update_next_owner+0x660/0x660 [ 55.415439] ? up_read+0x1a/0x110 [ 55.415451] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.415464] ? __do_page_fault+0x484/0xe90 [ 55.415480] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.415496] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.415509] do_group_exit+0x135/0x370 [ 55.415524] __x64_sys_exit_group+0x44/0x50 [ 55.415539] do_syscall_64+0xfd/0x620 [ 55.415554] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.415564] RIP: 0033:0x43ff78 [ 55.415573] Code: Bad RIP value. [ 55.415580] RSP: 002b:00007ffed0785788 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 55.415592] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff78 [ 55.415600] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 55.415608] RBP: 00000000004bf990 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 55.415615] R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001 [ 55.415622] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 55.417029] Kernel Offset: disabled