[ 44.252140] audit: type=1800 audit(1578575111.782:29): pid=7910 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 [ 44.280594] audit: type=1800 audit(1578575111.782:30): pid=7910 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 periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] 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 '10.128.0.200' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 52.280409] kauditd_printk_skb: 5 callbacks suppressed [ 52.280426] audit: type=1400 audit(1578575119.812:36): avc: denied { map } for pid=8094 comm="syz-executor232" path="/root/syz-executor232268499" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 52.351124] ================================================================== [ 52.351159] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 52.351170] Write of size 8 at addr ffff888084504e48 by task syz-executor232/8102 [ 52.351173] [ 52.351187] CPU: 0 PID: 8102 Comm: syz-executor232 Not tainted 4.19.94-syzkaller #0 [ 52.351196] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.351201] Call Trace: [ 52.351218] dump_stack+0x197/0x210 [ 52.351234] ? con_shutdown+0x85/0x90 [ 52.351251] print_address_description.cold+0x7c/0x20d [ 52.351264] ? con_shutdown+0x85/0x90 [ 52.351277] kasan_report.cold+0x8c/0x2ba [ 52.351292] ? set_palette+0x1c0/0x1c0 [ 52.351309] __asan_report_store8_noabort+0x17/0x20 [ 52.351323] con_shutdown+0x85/0x90 [ 52.351346] release_tty+0xe4/0x4d0 [ 52.351364] tty_release_struct+0x3c/0x50 [ 52.351380] tty_release+0xbcb/0xe90 [ 52.351403] ? tty_release_struct+0x50/0x50 [ 52.351417] __fput+0x2dd/0x8b0 [ 52.351439] ____fput+0x16/0x20 [ 52.351455] task_work_run+0x145/0x1c0 [ 52.351475] do_exit+0xc1f/0x30d0 [ 52.351500] ? mm_update_next_owner+0x660/0x660 [ 52.351515] ? up_read+0x1a/0x110 [ 52.351530] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 52.351544] ? __do_page_fault+0x484/0xe90 [ 52.351564] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.351579] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.351597] do_group_exit+0x135/0x370 [ 52.351615] __x64_sys_exit_group+0x44/0x50 [ 52.351631] do_syscall_64+0xfd/0x620 [ 52.351649] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.351660] RIP: 0033:0x43ff38 [ 52.351672] Code: Bad RIP value. [ 52.351679] RSP: 002b:00007ffd80340758 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 52.351693] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 52.351701] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 52.351710] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 52.351718] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 52.351726] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 52.351745] [ 52.351751] Allocated by task 8102: [ 52.351764] save_stack+0x45/0xd0 [ 52.351776] kasan_kmalloc+0xce/0xf0 [ 52.351788] kmem_cache_alloc_trace+0x152/0x760 [ 52.351801] vc_allocate+0x1f5/0x760 [ 52.351814] con_install+0x52/0x410 [ 52.351826] tty_init_dev+0xf7/0x460 [ 52.351838] tty_open+0x4bf/0xb70 [ 52.351849] chrdev_open+0x245/0x6b0 [ 52.351860] do_dentry_open+0x4c3/0x1210 [ 52.351871] vfs_open+0xa0/0xd0 [ 52.351882] path_openat+0x10d7/0x45e0 [ 52.351892] do_filp_open+0x1a1/0x280 [ 52.351903] do_sys_open+0x3fe/0x550 [ 52.351915] __x64_sys_open+0x7e/0xc0 [ 52.351929] do_syscall_64+0xfd/0x620 [ 52.351943] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.351946] [ 52.351952] Freed by task 8101: [ 52.351964] save_stack+0x45/0xd0 [ 52.351976] __kasan_slab_free+0x102/0x150 [ 52.351989] kasan_slab_free+0xe/0x10 [ 52.351999] kfree+0xcf/0x220 [ 52.352011] vt_disallocate_all+0x2bd/0x3e0 [ 52.352021] vt_ioctl+0xc38/0x2530 [ 52.352033] tty_ioctl+0x7f3/0x1510 [ 52.352045] do_vfs_ioctl+0xd5f/0x1380 [ 52.352056] ksys_ioctl+0xab/0xd0 [ 52.352068] __x64_sys_ioctl+0x73/0xb0 [ 52.352080] do_syscall_64+0xfd/0x620 [ 52.352094] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.352097] [ 52.352108] The buggy address belongs to the object at ffff888084504d40 [ 52.352108] which belongs to the cache kmalloc-2048 of size 2048 [ 52.352120] The buggy address is located 264 bytes inside of [ 52.352120] 2048-byte region [ffff888084504d40, ffff888084505540) [ 52.352125] The buggy address belongs to the page: [ 52.352137] page:ffffea0002114100 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 [ 52.352151] flags: 0xfffe0000008100(slab|head) [ 52.352170] raw: 00fffe0000008100 ffffea00027ef708 ffffea0001e40508 ffff88812c31cc40 [ 52.352187] raw: 0000000000000000 ffff8880845044c0 0000000100000003 0000000000000000 [ 52.352193] page dumped because: kasan: bad access detected [ 52.352196] [ 52.352200] Memory state around the buggy address: [ 52.352211] ffff888084504d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 52.352222] ffff888084504d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.352232] >ffff888084504e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.352238] ^ [ 52.352248] ffff888084504e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.352259] ffff888084504f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.352263] ================================================================== [ 52.352268] Disabling lock debugging due to kernel taint [ 52.352302] Kernel panic - not syncing: panic_on_warn set ... [ 52.352302] [ 52.352316] CPU: 0 PID: 8102 Comm: syz-executor232 Tainted: G B 4.19.94-syzkaller #0 [ 52.352323] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.352327] Call Trace: [ 52.352346] dump_stack+0x197/0x210 [ 52.352362] ? con_shutdown+0x85/0x90 [ 52.352373] panic+0x26a/0x50e [ 52.352384] ? __warn_printk+0xf3/0xf3 [ 52.352397] ? con_shutdown+0x85/0x90 [ 52.352416] ? trace_hardirqs_on+0x5e/0x220 [ 52.352428] ? trace_hardirqs_on+0x5e/0x220 [ 52.352443] ? con_shutdown+0x85/0x90 [ 52.352456] kasan_end_report+0x47/0x4f [ 52.352471] kasan_report.cold+0xa9/0x2ba [ 52.352484] ? set_palette+0x1c0/0x1c0 [ 52.352500] __asan_report_store8_noabort+0x17/0x20 [ 52.352513] con_shutdown+0x85/0x90 [ 52.352526] release_tty+0xe4/0x4d0 [ 52.352541] tty_release_struct+0x3c/0x50 [ 52.352555] tty_release+0xbcb/0xe90 [ 52.352572] ? tty_release_struct+0x50/0x50 [ 52.352585] __fput+0x2dd/0x8b0 [ 52.352601] ____fput+0x16/0x20 [ 52.352614] task_work_run+0x145/0x1c0 [ 52.352629] do_exit+0xc1f/0x30d0 [ 52.352647] ? mm_update_next_owner+0x660/0x660 [ 52.352659] ? up_read+0x1a/0x110 [ 52.352672] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 52.352685] ? __do_page_fault+0x484/0xe90 [ 52.352701] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.352716] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.352731] do_group_exit+0x135/0x370 [ 52.352746] __x64_sys_exit_group+0x44/0x50 [ 52.352760] do_syscall_64+0xfd/0x620 [ 52.352775] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.352784] RIP: 0033:0x43ff38 [ 52.352793] Code: Bad RIP value. [ 52.352800] RSP: 002b:00007ffd80340758 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 52.352812] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 52.352819] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 52.352827] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 52.352835] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 52.352841] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 52.354420] Kernel Offset: disabled