[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 66.556456][ T27] audit: type=1800 audit(1584965775.149:25): pid=9464 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 66.577237][ T27] audit: type=1800 audit(1584965775.159:26): pid=9464 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 66.597613][ T27] audit: type=1800 audit(1584965775.159:27): pid=9464 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?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 '10.128.1.19' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 75.865146][ T9626] ================================================================== [ 75.865204][ T9626] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 75.865215][ T9626] Write of size 8 at addr ffff8880a22db108 by task syz-executor292/9626 [ 75.865218][ T9626] [ 75.865232][ T9626] CPU: 0 PID: 9626 Comm: syz-executor292 Not tainted 5.6.0-rc6-syzkaller #0 [ 75.865239][ T9626] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.865243][ T9626] Call Trace: [ 75.865260][ T9626] dump_stack+0x188/0x20d [ 75.865273][ T9626] ? con_shutdown+0x7f/0x90 [ 75.865285][ T9626] ? con_shutdown+0x7f/0x90 [ 75.865304][ T9626] print_address_description.constprop.0.cold+0xd3/0x315 [ 75.865315][ T9626] ? con_shutdown+0x7f/0x90 [ 75.865328][ T9626] ? con_shutdown+0x7f/0x90 [ 75.865340][ T9626] __kasan_report.cold+0x1a/0x32 [ 75.865356][ T9626] ? con_shutdown+0x7f/0x90 [ 75.865373][ T9626] kasan_report+0xe/0x20 [ 75.865386][ T9626] con_shutdown+0x7f/0x90 [ 75.865397][ T9626] ? update_region+0x140/0x140 [ 75.865408][ T9626] release_tty+0xca/0x450 [ 75.865425][ T9626] tty_release_struct+0x37/0x50 [ 75.865438][ T9626] tty_release+0xbc7/0xe90 [ 75.865464][ T9626] ? do_tty_hangup+0x30/0x30 [ 75.865475][ T9626] __fput+0x2da/0x850 [ 75.865504][ T9626] task_work_run+0x13f/0x1b0 [ 75.865526][ T9626] do_exit+0xb34/0x2dd0 [ 75.865558][ T9626] ? mm_update_next_owner+0x7a0/0x7a0 [ 75.865572][ T9626] ? up_read+0x1ab/0x750 [ 75.865585][ T9626] ? mark_held_locks+0x9f/0xe0 [ 75.865601][ T9626] ? down_read_non_owner+0x470/0x470 [ 75.865622][ T9626] ? handle_mm_fault+0x491/0xa10 [ 75.865641][ T9626] do_group_exit+0x125/0x340 [ 75.865659][ T9626] __x64_sys_exit_group+0x3a/0x50 [ 75.865674][ T9626] do_syscall_64+0xf6/0x7d0 [ 75.865694][ T9626] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.865703][ T9626] RIP: 0033:0x43ff38 [ 75.865714][ T9626] Code: Bad RIP value. [ 75.865721][ T9626] RSP: 002b:00007ffca6966978 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 75.865732][ T9626] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 75.865738][ T9626] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 75.865745][ T9626] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 75.865751][ T9626] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 75.865757][ T9626] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 75.865784][ T9626] [ 75.865790][ T9626] Allocated by task 9626: [ 75.865801][ T9626] save_stack+0x1b/0x80 [ 75.865813][ T9626] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 75.865824][ T9626] kmem_cache_alloc_trace+0x153/0x7d0 [ 75.865835][ T9626] vc_allocate+0x1e2/0x6e0 [ 75.865844][ T9626] con_install+0x4f/0x400 [ 75.865853][ T9626] tty_init_dev+0xf5/0x460 [ 75.865863][ T9626] tty_open+0x47f/0xb30 [ 75.865873][ T9626] chrdev_open+0x219/0x5c0 [ 75.865884][ T9626] do_dentry_open+0x4a2/0x1250 [ 75.865894][ T9626] path_openat+0x122a/0x32b0 [ 75.865905][ T9626] do_filp_open+0x192/0x260 [ 75.865914][ T9626] do_sys_openat2+0x54c/0x740 [ 75.865925][ T9626] do_sys_open+0xc3/0x140 [ 75.865936][ T9626] do_syscall_64+0xf6/0x7d0 [ 75.865947][ T9626] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.865950][ T9626] [ 75.865955][ T9626] Freed by task 9629: [ 75.865965][ T9626] save_stack+0x1b/0x80 [ 75.865975][ T9626] __kasan_slab_free+0xf7/0x140 [ 75.865985][ T9626] kfree+0x109/0x2b0 [ 75.865996][ T9626] vt_disallocate_all+0x293/0x3b0 [ 75.866014][ T9626] vt_ioctl+0xb79/0x2470 [ 75.866023][ T9626] tty_ioctl+0xedd/0x1440 [ 75.866035][ T9626] ksys_ioctl+0x11a/0x180 [ 75.866046][ T9626] __x64_sys_ioctl+0x6f/0xb0 [ 75.866058][ T9626] do_syscall_64+0xf6/0x7d0 [ 75.866069][ T9626] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.866073][ T9626] [ 75.866081][ T9626] The buggy address belongs to the object at ffff8880a22db000 [ 75.866081][ T9626] which belongs to the cache kmalloc-2k of size 2048 [ 75.866092][ T9626] The buggy address is located 264 bytes inside of [ 75.866092][ T9626] 2048-byte region [ffff8880a22db000, ffff8880a22db800) [ 75.866096][ T9626] The buggy address belongs to the page: [ 75.866107][ T9626] page:ffffea000288b6c0 refcount:1 mapcount:0 mapping:ffff8880aa000e00 index:0x0 [ 75.866116][ T9626] flags: 0xfffe0000000200(slab) [ 75.866132][ T9626] raw: 00fffe0000000200 ffffea00029b8f08 ffffea000260f5c8 ffff8880aa000e00 [ 75.866146][ T9626] raw: 0000000000000000 ffff8880a22db000 0000000100000001 0000000000000000 [ 75.866151][ T9626] page dumped because: kasan: bad access detected [ 75.866155][ T9626] [ 75.866159][ T9626] Memory state around the buggy address: [ 75.866168][ T9626] ffff8880a22db000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.866178][ T9626] ffff8880a22db080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.866187][ T9626] >ffff8880a22db100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.866192][ T9626] ^ [ 75.866201][ T9626] ffff8880a22db180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.866211][ T9626] ffff8880a22db200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.866215][ T9626] ================================================================== [ 75.866219][ T9626] Disabling lock debugging due to kernel taint [ 75.866225][ T9626] Kernel panic - not syncing: panic_on_warn set ... [ 75.866237][ T9626] CPU: 0 PID: 9626 Comm: syz-executor292 Tainted: G B 5.6.0-rc6-syzkaller #0 [ 75.866243][ T9626] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.866246][ T9626] Call Trace: [ 75.866259][ T9626] dump_stack+0x188/0x20d [ 75.866275][ T9626] panic+0x2e3/0x75c [ 75.866287][ T9626] ? add_taint.cold+0x16/0x16 [ 75.866306][ T9626] ? print_shadow_for_address+0xb8/0x114 [ 75.866318][ T9626] ? trace_hardirqs_on+0x55/0x220 [ 75.866331][ T9626] ? con_shutdown+0x7f/0x90 [ 75.866344][ T9626] end_report+0x43/0x49 [ 75.866354][ T9626] ? con_shutdown+0x7f/0x90 [ 75.866365][ T9626] __kasan_report.cold+0xd/0x32 [ 75.866378][ T9626] ? con_shutdown+0x7f/0x90 [ 75.866391][ T9626] kasan_report+0xe/0x20 [ 75.866402][ T9626] con_shutdown+0x7f/0x90 [ 75.866412][ T9626] ? update_region+0x140/0x140 [ 75.866421][ T9626] release_tty+0xca/0x450 [ 75.866434][ T9626] tty_release_struct+0x37/0x50 [ 75.866445][ T9626] tty_release+0xbc7/0xe90 [ 75.866463][ T9626] ? do_tty_hangup+0x30/0x30 [ 75.866471][ T9626] __fput+0x2da/0x850 [ 75.866490][ T9626] task_work_run+0x13f/0x1b0 [ 75.866506][ T9626] do_exit+0xb34/0x2dd0 [ 75.866526][ T9626] ? mm_update_next_owner+0x7a0/0x7a0 [ 75.866538][ T9626] ? up_read+0x1ab/0x750 [ 75.866549][ T9626] ? mark_held_locks+0x9f/0xe0 [ 75.866562][ T9626] ? down_read_non_owner+0x470/0x470 [ 75.866577][ T9626] ? handle_mm_fault+0x491/0xa10 [ 75.866590][ T9626] do_group_exit+0x125/0x340 [ 75.866603][ T9626] __x64_sys_exit_group+0x3a/0x50 [ 75.866615][ T9626] do_syscall_64+0xf6/0x7d0 [ 75.866630][ T9626] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.866638][ T9626] RIP: 0033:0x43ff38 [ 75.866645][ T9626] Code: Bad RIP value. [ 75.866651][ T9626] RSP: 002b:00007ffca6966978 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 75.866661][ T9626] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 75.866668][ T9626] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 75.866674][ T9626] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 75.866680][ T9626] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 75.866687][ T9626] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 75.868045][ T9626] Kernel Offset: disabled [ 76.596230][ T9626] Rebooting in 86400 seconds..