[ 46.705787] audit: type=1800 audit(1583197764.442:29): pid=7780 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 [ 46.729706] audit: type=1800 audit(1583197764.442:30): pid=7780 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 '10.128.0.102' (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: [ 55.153051] kauditd_printk_skb: 5 callbacks suppressed [ 55.153065] audit: type=1400 audit(1583197772.892:36): avc: denied { map } for pid=7967 comm="syz-executor446" path="/root/syz-executor446812061" 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 executing program [ 55.252019] ================================================================== [ 55.252058] BUG: KASAN: use-after-free in con_shutdown+0x7f/0x90 [ 55.252069] Write of size 8 at addr ffff8880a4916b88 by task syz-executor446/7979 [ 55.252072] [ 55.252085] CPU: 1 PID: 7979 Comm: syz-executor446 Not tainted 4.19.107-syzkaller #0 [ 55.252092] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.252097] Call Trace: [ 55.252112] dump_stack+0x188/0x20d [ 55.252128] ? con_shutdown+0x7f/0x90 [ 55.252144] print_address_description.cold+0x7c/0x212 [ 55.252158] ? con_shutdown+0x7f/0x90 [ 55.252170] kasan_report.cold+0x88/0x2b9 [ 55.252182] ? set_palette+0x1b0/0x1b0 [ 55.252196] con_shutdown+0x7f/0x90 [ 55.252209] release_tty+0xda/0x4c0 [ 55.252224] tty_release_struct+0x37/0x50 [ 55.252236] tty_release+0xbc7/0xe90 [ 55.252256] ? tty_release_struct+0x50/0x50 [ 55.252269] __fput+0x2cd/0x890 [ 55.252287] task_work_run+0x13f/0x1b0 [ 55.252305] do_exit+0xbcd/0x2f30 [ 55.252326] ? mm_update_next_owner+0x650/0x650 [ 55.252343] ? up_read+0x17/0x110 [ 55.252356] ? __do_page_fault+0x44e/0xdd0 [ 55.252375] do_group_exit+0x125/0x350 [ 55.252391] __x64_sys_exit_group+0x3a/0x50 [ 55.252405] do_syscall_64+0xf9/0x620 [ 55.252422] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.252432] RIP: 0033:0x43ff38 [ 55.252444] Code: Bad RIP value. [ 55.252451] RSP: 002b:00007ffdb7dfb5f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 55.252464] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 55.252471] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 55.252479] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 55.252487] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 55.252494] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 55.252511] [ 55.252518] Allocated by task 7979: [ 55.252530] kasan_kmalloc+0xbf/0xe0 [ 55.252540] kmem_cache_alloc_trace+0x14d/0x7a0 [ 55.252551] vc_allocate+0x1db/0x6d0 [ 55.252561] con_install+0x4f/0x400 [ 55.252572] tty_init_dev+0xee/0x450 [ 55.252582] tty_open+0x4b0/0xb00 [ 55.252591] chrdev_open+0x219/0x5c0 [ 55.252601] do_dentry_open+0x4a8/0x1160 [ 55.252613] path_openat+0x1031/0x4200 [ 55.252622] do_filp_open+0x1a1/0x280 [ 55.252631] do_sys_open+0x3c0/0x500 [ 55.252642] do_syscall_64+0xf9/0x620 [ 55.252654] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.252657] [ 55.252663] Freed by task 7977: [ 55.252681] __kasan_slab_free+0xf7/0x140 [ 55.252690] kfree+0xce/0x220 [ 55.252702] vt_disallocate_all+0x293/0x3b0 [ 55.252713] vt_ioctl+0xb79/0x2310 [ 55.252723] tty_ioctl+0x7a1/0x1420 [ 55.252734] do_vfs_ioctl+0xcda/0x12e0 [ 55.252743] ksys_ioctl+0x9b/0xc0 [ 55.252754] __x64_sys_ioctl+0x6f/0xb0 [ 55.252765] do_syscall_64+0xf9/0x620 [ 55.252777] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.252780] [ 55.252790] The buggy address belongs to the object at ffff8880a4916a80 [ 55.252790] which belongs to the cache kmalloc-2048 of size 2048 [ 55.252800] The buggy address is located 264 bytes inside of [ 55.252800] 2048-byte region [ffff8880a4916a80, ffff8880a4917280) [ 55.252805] The buggy address belongs to the page: [ 55.252815] page:ffffea0002924580 count:1 mapcount:0 mapping:ffff88812c3dcc40 index:0x0 compound_mapcount: 0 [ 55.252829] flags: 0xfffe0000008100(slab|head) [ 55.252845] raw: 00fffe0000008100 ffffea0002922a88 ffffea0002916208 ffff88812c3dcc40 [ 55.252859] raw: 0000000000000000 ffff8880a4916200 0000000100000003 0000000000000000 [ 55.252865] page dumped because: kasan: bad access detected [ 55.252868] [ 55.252872] Memory state around the buggy address: [ 55.252882] ffff8880a4916a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.252892] ffff8880a4916b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.252901] >ffff8880a4916b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.252906] ^ [ 55.252915] ffff8880a4916c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.252924] ffff8880a4916c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.252929] ================================================================== [ 55.252933] Disabling lock debugging due to kernel taint [ 55.252975] Kernel panic - not syncing: panic_on_warn set ... [ 55.252975] [ 55.252988] CPU: 1 PID: 7979 Comm: syz-executor446 Tainted: G B 4.19.107-syzkaller #0 [ 55.252994] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.252997] Call Trace: [ 55.253011] dump_stack+0x188/0x20d [ 55.253025] panic+0x26a/0x50e [ 55.253038] ? __warn_printk+0xf3/0xf3 [ 55.253048] ? retint_kernel+0x2d/0x2d [ 55.253065] ? trace_hardirqs_on+0x55/0x210 [ 55.253076] ? con_shutdown+0x7f/0x90 [ 55.253086] kasan_end_report+0x43/0x49 [ 55.253099] kasan_report.cold+0xa4/0x2b9 [ 55.253111] ? set_palette+0x1b0/0x1b0 [ 55.253122] con_shutdown+0x7f/0x90 [ 55.253132] release_tty+0xda/0x4c0 [ 55.253145] tty_release_struct+0x37/0x50 [ 55.253156] tty_release+0xbc7/0xe90 [ 55.253171] ? tty_release_struct+0x50/0x50 [ 55.253181] __fput+0x2cd/0x890 [ 55.253195] task_work_run+0x13f/0x1b0 [ 55.253207] do_exit+0xbcd/0x2f30 [ 55.253224] ? mm_update_next_owner+0x650/0x650 [ 55.253236] ? up_read+0x17/0x110 [ 55.253248] ? __do_page_fault+0x44e/0xdd0 [ 55.253262] do_group_exit+0x125/0x350 [ 55.253275] __x64_sys_exit_group+0x3a/0x50 [ 55.253287] do_syscall_64+0xf9/0x620 [ 55.253301] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.253309] RIP: 0033:0x43ff38 [ 55.253317] Code: Bad RIP value. [ 55.253324] RSP: 002b:00007ffdb7dfb5f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 55.253335] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 55.253341] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 55.253348] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 55.253354] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 55.253361] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 55.254657] Kernel Offset: disabled [ 55.833966] Rebooting in 86400 seconds..