[ 42.460706] audit: type=1800 audit(1581069642.771:29): pid=7825 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 [ 42.497065] audit: type=1800 audit(1581069642.781:30): pid=7825 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 OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.161' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 52.857085] kauditd_printk_skb: 5 callbacks suppressed [ 52.857101] audit: type=1400 audit(1581069653.171:36): avc: denied { map } for pid=8013 comm="syz-executor189" path="/root/syz-executor189524399" 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 [ 52.934103] ================================================================== [ 52.934141] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 52.934154] Write of size 8 at addr ffff8880a97929c8 by task syz-executor189/8025 [ 52.934158] [ 52.934174] CPU: 1 PID: 8025 Comm: syz-executor189 Not tainted 4.19.102-syzkaller #0 [ 52.934182] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.934187] Call Trace: [ 52.934206] dump_stack+0x197/0x210 [ 52.934225] ? con_shutdown+0x85/0x90 [ 52.934244] print_address_description.cold+0x7c/0x20d [ 52.934260] ? con_shutdown+0x85/0x90 [ 52.934276] kasan_report.cold+0x8c/0x2ba [ 52.934292] ? set_palette+0x1c0/0x1c0 [ 52.934310] __asan_report_store8_noabort+0x17/0x20 [ 52.934325] con_shutdown+0x85/0x90 [ 52.934340] release_tty+0xe4/0x4d0 [ 52.934358] tty_release_struct+0x3c/0x50 [ 52.934373] tty_release+0xbcb/0xe90 [ 52.934397] ? tty_release_struct+0x50/0x50 [ 52.934412] __fput+0x2dd/0x8b0 [ 52.934435] ____fput+0x16/0x20 [ 52.934449] task_work_run+0x145/0x1c0 [ 52.934470] do_exit+0xc1f/0x30d0 [ 52.934499] ? mm_update_next_owner+0x660/0x660 [ 52.934513] ? up_read+0x1a/0x110 [ 52.934526] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 52.934540] ? __do_page_fault+0x484/0xe90 [ 52.934561] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.934576] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.934593] do_group_exit+0x135/0x370 [ 52.934611] __x64_sys_exit_group+0x44/0x50 [ 52.934628] do_syscall_64+0xfd/0x620 [ 52.934648] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.934659] RIP: 0033:0x43ff38 [ 52.934672] Code: Bad RIP value. [ 52.934679] RSP: 002b:00007ffccfa48cd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 52.934694] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 52.934702] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 52.934711] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 52.934720] R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001 [ 52.934727] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 52.934746] [ 52.934753] Allocated by task 8025: [ 52.934766] save_stack+0x45/0xd0 [ 52.934779] kasan_kmalloc+0xce/0xf0 [ 52.934791] kmem_cache_alloc_trace+0x152/0x760 [ 52.934804] vc_allocate+0x1f5/0x760 [ 52.934816] con_install+0x52/0x410 [ 52.934829] tty_init_dev+0xf7/0x460 [ 52.934847] tty_open+0x4bf/0xb70 [ 52.934859] chrdev_open+0x245/0x6b0 [ 52.934870] do_dentry_open+0x4c3/0x1210 [ 52.934881] vfs_open+0xa0/0xd0 [ 52.934896] path_openat+0x10d8/0x44a0 [ 52.934907] do_filp_open+0x1a1/0x280 [ 52.934918] do_sys_open+0x3fe/0x550 [ 52.934929] __x64_sys_open+0x7e/0xc0 [ 52.934943] do_syscall_64+0xfd/0x620 [ 52.934958] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.934962] [ 52.934967] Freed by task 8023: [ 52.934979] save_stack+0x45/0xd0 [ 52.935037] __kasan_slab_free+0x102/0x150 [ 52.935057] kasan_slab_free+0xe/0x10 [ 52.935067] kfree+0xcf/0x220 [ 52.935081] vt_disallocate_all+0x2bd/0x3e0 [ 52.935096] vt_ioctl+0xc38/0x2530 [ 52.935106] tty_ioctl+0x7f3/0x1510 [ 52.935118] do_vfs_ioctl+0xd5f/0x1380 [ 52.935130] ksys_ioctl+0xab/0xd0 [ 52.935142] __x64_sys_ioctl+0x73/0xb0 [ 52.935157] do_syscall_64+0xfd/0x620 [ 52.935172] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.935176] [ 52.935187] The buggy address belongs to the object at ffff8880a97928c0 [ 52.935187] which belongs to the cache kmalloc-2048 of size 2048 [ 52.935200] The buggy address is located 264 bytes inside of [ 52.935200] 2048-byte region [ffff8880a97928c0, ffff8880a97930c0) [ 52.935204] The buggy address belongs to the page: [ 52.935217] page:ffffea0002a5e480 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 [ 52.935229] flags: 0xfffe0000008100(slab|head) [ 52.935246] raw: 00fffe0000008100 ffffea0002342888 ffffea0002048608 ffff88812c31cc40 [ 52.935261] raw: 0000000000000000 ffff8880a9792040 0000000100000003 0000000000000000 [ 52.935267] page dumped because: kasan: bad access detected [ 52.935270] [ 52.935274] Memory state around the buggy address: [ 52.935285] ffff8880a9792880: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 52.935295] ffff8880a9792900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.935305] >ffff8880a9792980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.935310] ^ [ 52.935319] ffff8880a9792a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.935330] ffff8880a9792a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.935334] ================================================================== [ 52.935339] Disabling lock debugging due to kernel taint [ 52.935346] Kernel panic - not syncing: panic_on_warn set ... [ 52.935346] [ 52.935360] CPU: 1 PID: 8025 Comm: syz-executor189 Tainted: G B 4.19.102-syzkaller #0 [ 52.935367] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.935371] Call Trace: [ 52.935387] dump_stack+0x197/0x210 [ 52.935401] ? con_shutdown+0x85/0x90 [ 52.935415] panic+0x26a/0x50e [ 52.935429] ? __warn_printk+0xf3/0xf3 [ 52.935444] ? lock_downgrade+0x880/0x880 [ 52.935458] ? trace_hardirqs_on+0x67/0x220 [ 52.935471] ? trace_hardirqs_on+0x5e/0x220 [ 52.935486] ? con_shutdown+0x85/0x90 [ 52.935500] kasan_end_report+0x47/0x4f [ 52.935585] kasan_report.cold+0xa9/0x2ba [ 52.935601] ? set_palette+0x1c0/0x1c0 [ 52.935614] __asan_report_store8_noabort+0x17/0x20 [ 52.935623] con_shutdown+0x85/0x90 [ 52.935633] release_tty+0xe4/0x4d0 [ 52.935644] tty_release_struct+0x3c/0x50 [ 52.935653] tty_release+0xbcb/0xe90 [ 52.935666] ? tty_release_struct+0x50/0x50 [ 52.935676] __fput+0x2dd/0x8b0 [ 52.935689] ____fput+0x16/0x20 [ 52.935699] task_work_run+0x145/0x1c0 [ 52.935712] do_exit+0xc1f/0x30d0 [ 52.935727] ? mm_update_next_owner+0x660/0x660 [ 52.935739] ? up_read+0x1a/0x110 [ 52.935752] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 52.935764] ? __do_page_fault+0x484/0xe90 [ 52.935781] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.935796] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.935810] do_group_exit+0x135/0x370 [ 52.935823] __x64_sys_exit_group+0x44/0x50 [ 52.935835] do_syscall_64+0xfd/0x620 [ 52.935851] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 52.935861] RIP: 0033:0x43ff38 [ 52.935871] Code: Bad RIP value. [ 52.935878] RSP: 002b:00007ffccfa48cd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 52.935890] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 52.935897] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 52.935905] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 52.935911] R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001 [ 52.935919] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 52.937429] Kernel Offset: disabled [ 53.595813] Rebooting in 86400 seconds..