[ 45.122384] audit: type=1800 audit(1579616272.033:30): pid=8095 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 syzkaller login: [ 48.712973] kauditd_printk_skb: 4 callbacks suppressed [ 48.712989] audit: type=1400 audit(1579616275.663:35): avc: denied { map } for pid=8268 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 '10.128.0.64' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program [ 55.480464] audit: type=1400 audit(1579616282.423:36): avc: denied { map } for pid=8280 comm="syz-executor709" path="/root/syz-executor709352927" 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 [ 55.539843] ================================================================== [ 55.539883] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 55.539894] Write of size 8 at addr ffff88809eb47508 by task syz-executor709/8287 [ 55.539898] [ 55.539913] CPU: 1 PID: 8287 Comm: syz-executor709 Not tainted 4.19.97-syzkaller #0 [ 55.539921] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.539926] Call Trace: [ 55.539943] dump_stack+0x197/0x210 [ 55.539962] ? con_shutdown+0x85/0x90 [ 55.539980] print_address_description.cold+0x7c/0x20d [ 55.539998] ? con_shutdown+0x85/0x90 [ 55.540013] kasan_report.cold+0x8c/0x2ba [ 55.540030] ? set_palette+0x1c0/0x1c0 [ 55.540048] __asan_report_store8_noabort+0x17/0x20 [ 55.540063] con_shutdown+0x85/0x90 [ 55.540078] release_tty+0xe4/0x4d0 [ 55.540096] tty_release_struct+0x3c/0x50 [ 55.540112] tty_release+0xbcb/0xe90 [ 55.540136] ? tty_release_struct+0x50/0x50 [ 55.540151] __fput+0x2dd/0x8b0 [ 55.540173] ____fput+0x16/0x20 [ 55.540187] task_work_run+0x145/0x1c0 [ 55.540214] do_exit+0xc1f/0x30d0 [ 55.540239] ? mm_update_next_owner+0x660/0x660 [ 55.540254] ? up_read+0x1a/0x110 [ 55.540268] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.540283] ? __do_page_fault+0x484/0xe90 [ 55.540304] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.540321] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.540339] do_group_exit+0x135/0x370 [ 55.540359] __x64_sys_exit_group+0x44/0x50 [ 55.540375] do_syscall_64+0xfd/0x620 [ 55.540399] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.540411] RIP: 0033:0x43ff38 [ 55.540424] 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 [ 55.540432] RSP: 002b:00007fff504e1458 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 55.540445] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 55.540453] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 55.540462] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 55.540471] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 55.540478] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 55.540498] [ 55.540505] Allocated by task 8287: [ 55.540518] save_stack+0x45/0xd0 [ 55.540530] kasan_kmalloc+0xce/0xf0 [ 55.540542] kmem_cache_alloc_trace+0x152/0x760 [ 55.540556] vc_allocate+0x1f5/0x760 [ 55.540570] con_install+0x52/0x410 [ 55.540582] tty_init_dev+0xf7/0x460 [ 55.540595] tty_open+0x4bf/0xb70 [ 55.540606] chrdev_open+0x245/0x6b0 [ 55.540617] do_dentry_open+0x4c3/0x1210 [ 55.540635] vfs_open+0xa0/0xd0 [ 55.540644] path_openat+0x10d7/0x45e0 [ 55.540653] do_filp_open+0x1a1/0x280 [ 55.540663] do_sys_open+0x3fe/0x550 [ 55.540673] __x64_sys_open+0x7e/0xc0 [ 55.540685] do_syscall_64+0xfd/0x620 [ 55.540699] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.540703] [ 55.540709] Freed by task 8288: [ 55.540721] save_stack+0x45/0xd0 [ 55.540734] __kasan_slab_free+0x102/0x150 [ 55.540746] kasan_slab_free+0xe/0x10 [ 55.540757] kfree+0xcf/0x220 [ 55.540769] vt_disallocate_all+0x2bd/0x3e0 [ 55.540779] vt_ioctl+0xc38/0x2530 [ 55.540791] tty_ioctl+0x7f3/0x1510 [ 55.540804] do_vfs_ioctl+0xd5f/0x1380 [ 55.540815] ksys_ioctl+0xab/0xd0 [ 55.540828] __x64_sys_ioctl+0x73/0xb0 [ 55.540841] do_syscall_64+0xfd/0x620 [ 55.540854] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.540858] [ 55.540868] The buggy address belongs to the object at ffff88809eb47400 [ 55.540868] which belongs to the cache kmalloc-2048 of size 2048 [ 55.540880] The buggy address is located 264 bytes inside of [ 55.540880] 2048-byte region [ffff88809eb47400, ffff88809eb47c00) [ 55.540885] The buggy address belongs to the page: [ 55.540897] page:ffffea00027ad180 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 [ 55.540911] flags: 0xfffe0000008100(slab|head) [ 55.540929] raw: 00fffe0000008100 ffffea0002796c88 ffffea00027c7b88 ffff88812c31cc40 [ 55.540945] raw: 0000000000000000 ffff88809eb46300 0000000100000003 0000000000000000 [ 55.540950] page dumped because: kasan: bad access detected [ 55.540953] [ 55.540958] Memory state around the buggy address: [ 55.540975] ffff88809eb47400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.540989] ffff88809eb47480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.541000] >ffff88809eb47500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.541005] ^ [ 55.541016] ffff88809eb47580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.541026] ffff88809eb47600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.541031] ================================================================== [ 55.541036] Disabling lock debugging due to kernel taint [ 55.541139] Kernel panic - not syncing: panic_on_warn set ... [ 55.541139] [ 55.541154] CPU: 1 PID: 8287 Comm: syz-executor709 Tainted: G B 4.19.97-syzkaller #0 [ 55.541161] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.541164] Call Trace: [ 55.541180] dump_stack+0x197/0x210 [ 55.541196] ? con_shutdown+0x85/0x90 [ 55.541206] panic+0x26a/0x50e [ 55.541217] ? __warn_printk+0xf3/0xf3 [ 55.541233] ? con_shutdown+0x85/0x90 [ 55.541246] ? preempt_schedule+0x4b/0x60 [ 55.541260] ? ___preempt_schedule+0x16/0x18 [ 55.541274] ? trace_hardirqs_on+0x5e/0x220 [ 55.541290] ? con_shutdown+0x85/0x90 [ 55.541305] kasan_end_report+0x47/0x4f [ 55.541320] kasan_report.cold+0xa9/0x2ba [ 55.541334] ? set_palette+0x1c0/0x1c0 [ 55.541351] __asan_report_store8_noabort+0x17/0x20 [ 55.541364] con_shutdown+0x85/0x90 [ 55.541378] release_tty+0xe4/0x4d0 [ 55.541438] tty_release_struct+0x3c/0x50 [ 55.541459] tty_release+0xbcb/0xe90 [ 55.541475] ? tty_release_struct+0x50/0x50 [ 55.541490] __fput+0x2dd/0x8b0 [ 55.541505] ____fput+0x16/0x20 [ 55.541518] task_work_run+0x145/0x1c0 [ 55.541532] do_exit+0xc1f/0x30d0 [ 55.541550] ? mm_update_next_owner+0x660/0x660 [ 55.541563] ? up_read+0x1a/0x110 [ 55.541576] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.541589] ? __do_page_fault+0x484/0xe90 [ 55.541606] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.541620] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.541635] do_group_exit+0x135/0x370 [ 55.541651] __x64_sys_exit_group+0x44/0x50 [ 55.541666] do_syscall_64+0xfd/0x620 [ 55.541682] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 55.541692] RIP: 0033:0x43ff38 [ 55.541705] 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 [ 55.541712] RSP: 002b:00007fff504e1458 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 55.541724] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 55.541731] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 55.541739] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 55.541747] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 55.541754] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 55.543308] Kernel Offset: disabled