[....] Starting periodic command scheduler: cron[?25l[?1c[ 45.393318] audit: type=1800 audit(1579219320.964:30): pid=8098 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 7[ 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 syzkaller login: [ 49.766210] kauditd_printk_skb: 4 callbacks suppressed [ 49.766232] audit: type=1400 audit(1579219325.344:35): avc: denied { map } for pid=8272 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 Warning: Permanently added '10.128.0.176' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program [ 65.815320] audit: type=1400 audit(1579219341.384:36): avc: denied { map } for pid=8284 comm="syz-executor769" path="/root/syz-executor769777838" 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 [ 65.874429] ================================================================== [ 65.874463] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 65.874472] Write of size 8 at addr ffff8880968e2a08 by task syz-executor769/8295 [ 65.874475] [ 65.874487] CPU: 0 PID: 8295 Comm: syz-executor769 Not tainted 4.19.96-syzkaller #0 [ 65.874493] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.874497] Call Trace: [ 65.874518] dump_stack+0x197/0x210 [ 65.874533] ? con_shutdown+0x85/0x90 [ 65.874548] print_address_description.cold+0x7c/0x20d [ 65.874561] ? con_shutdown+0x85/0x90 [ 65.874573] kasan_report.cold+0x8c/0x2ba [ 65.874586] ? set_palette+0x1c0/0x1c0 [ 65.874600] __asan_report_store8_noabort+0x17/0x20 [ 65.874611] con_shutdown+0x85/0x90 [ 65.874624] release_tty+0xe4/0x4d0 [ 65.874638] tty_release_struct+0x3c/0x50 [ 65.874651] tty_release+0xbcb/0xe90 [ 65.874669] ? tty_release_struct+0x50/0x50 [ 65.874683] __fput+0x2dd/0x8b0 [ 65.874700] ____fput+0x16/0x20 [ 65.874713] task_work_run+0x145/0x1c0 [ 65.874730] do_exit+0xc1f/0x30d0 [ 65.874750] ? mm_update_next_owner+0x660/0x660 [ 65.874762] ? up_read+0x1a/0x110 [ 65.874773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.874785] ? __do_page_fault+0x484/0xe90 [ 65.874819] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.874831] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.874844] do_group_exit+0x135/0x370 [ 65.874859] __x64_sys_exit_group+0x44/0x50 [ 65.874872] do_syscall_64+0xfd/0x620 [ 65.874887] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.874896] RIP: 0033:0x43ff38 [ 65.874907] Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 [ 65.874913] RSP: 002b:00007ffc502c02f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 65.874924] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 65.874930] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 65.874937] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 65.874943] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 65.874949] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 65.874964] [ 65.874969] Allocated by task 8295: [ 65.874980] save_stack+0x45/0xd0 [ 65.874990] kasan_kmalloc+0xce/0xf0 [ 65.875000] kmem_cache_alloc_trace+0x152/0x760 [ 65.875010] vc_allocate+0x1f5/0x760 [ 65.875021] con_install+0x52/0x410 [ 65.875031] tty_init_dev+0xf7/0x460 [ 65.875041] tty_open+0x4bf/0xb70 [ 65.875049] chrdev_open+0x245/0x6b0 [ 65.875058] do_dentry_open+0x4c3/0x1210 [ 65.875066] vfs_open+0xa0/0xd0 [ 65.875074] path_openat+0x10d7/0x45e0 [ 65.875082] do_filp_open+0x1a1/0x280 [ 65.875091] do_sys_open+0x3fe/0x550 [ 65.875099] __x64_sys_open+0x7e/0xc0 [ 65.875110] do_syscall_64+0xfd/0x620 [ 65.875120] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.875122] [ 65.875127] Freed by task 8291: [ 65.875136] save_stack+0x45/0xd0 [ 65.875147] __kasan_slab_free+0x102/0x150 [ 65.875158] kasan_slab_free+0xe/0x10 [ 65.875167] kfree+0xcf/0x220 [ 65.875177] vt_disallocate_all+0x2bd/0x3e0 [ 65.875185] vt_ioctl+0xc38/0x2530 [ 65.875196] tty_ioctl+0x7f3/0x1510 [ 65.875208] do_vfs_ioctl+0xd5f/0x1380 [ 65.875218] ksys_ioctl+0xab/0xd0 [ 65.875228] __x64_sys_ioctl+0x73/0xb0 [ 65.875240] do_syscall_64+0xfd/0x620 [ 65.875253] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.875256] [ 65.875265] The buggy address belongs to the object at ffff8880968e2900 [ 65.875265] which belongs to the cache kmalloc-2048 of size 2048 [ 65.875275] The buggy address is located 264 bytes inside of [ 65.875275] 2048-byte region [ffff8880968e2900, ffff8880968e3100) [ 65.875278] The buggy address belongs to the page: [ 65.875288] page:ffffea00025a3880 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 [ 65.875302] flags: 0xfffe0000008100(slab|head) [ 65.875319] raw: 00fffe0000008100 ffffea0001f8d688 ffffea00025dd008 ffff88812c31cc40 [ 65.875333] raw: 0000000000000000 ffff8880968e2080 0000000100000003 0000000000000000 [ 65.875339] page dumped because: kasan: bad access detected [ 65.875343] [ 65.875347] Memory state around the buggy address: [ 65.875357] ffff8880968e2900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.875367] ffff8880968e2980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.875376] >ffff8880968e2a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.875380] ^ [ 65.875390] ffff8880968e2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.875399] ffff8880968e2b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 65.875404] ================================================================== [ 65.875409] Disabling lock debugging due to kernel taint [ 65.876838] Kernel panic - not syncing: panic_on_warn set ... [ 65.876838] [ 65.876855] CPU: 0 PID: 8295 Comm: syz-executor769 Tainted: G B 4.19.96-syzkaller #0 [ 65.876863] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.876866] Call Trace: [ 65.876884] dump_stack+0x197/0x210 [ 65.876902] ? con_shutdown+0x85/0x90 [ 65.876914] panic+0x26a/0x50e [ 65.876925] ? __warn_printk+0xf3/0xf3 [ 65.876941] ? con_shutdown+0x85/0x90 [ 65.876956] ? preempt_schedule+0x4b/0x60 [ 65.876972] ? ___preempt_schedule+0x16/0x18 [ 65.876987] ? trace_hardirqs_on+0x5e/0x220 [ 65.877003] ? con_shutdown+0x85/0x90 [ 65.877017] kasan_end_report+0x47/0x4f [ 65.877161] kasan_report.cold+0xa9/0x2ba [ 65.877176] ? set_palette+0x1c0/0x1c0 [ 65.877190] __asan_report_store8_noabort+0x17/0x20 [ 65.877202] con_shutdown+0x85/0x90 [ 65.877215] release_tty+0xe4/0x4d0 [ 65.877227] tty_release_struct+0x3c/0x50 [ 65.877239] tty_release+0xbcb/0xe90 [ 65.877256] ? tty_release_struct+0x50/0x50 [ 65.877270] __fput+0x2dd/0x8b0 [ 65.877286] ____fput+0x16/0x20 [ 65.877298] task_work_run+0x145/0x1c0 [ 65.877314] do_exit+0xc1f/0x30d0 [ 65.877330] ? mm_update_next_owner+0x660/0x660 [ 65.877343] ? up_read+0x1a/0x110 [ 65.877355] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.877368] ? __do_page_fault+0x484/0xe90 [ 65.877383] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.877396] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 65.877410] do_group_exit+0x135/0x370 [ 65.877425] __x64_sys_exit_group+0x44/0x50 [ 65.877438] do_syscall_64+0xfd/0x620 [ 65.877455] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.877463] RIP: 0033:0x43ff38 [ 65.877476] Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 [ 65.877483] RSP: 002b:00007ffc502c02f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 65.877494] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 65.877501] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 65.877509] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 65.877516] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 65.877522] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 65.879154] Kernel Offset: disabled [ 66.578885] Rebooting in 86400 seconds..