[ 45.892531] audit: type=1800 audit(1582217415.422:29): pid=8135 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 [ 45.929295] audit: type=1800 audit(1582217415.422:30): pid=8135 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 mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] 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 '10.128.0.235' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 54.420002] kauditd_printk_skb: 5 callbacks suppressed [ 54.420017] audit: type=1400 audit(1582217423.952:36): avc: denied { map } for pid=8322 comm="syz-executor461" path="/root/syz-executor461751224" 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 [ 54.508575] ================================================================== [ 54.508615] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 54.508627] Write of size 8 at addr ffff8880a8392208 by task syz-executor461/8330 [ 54.508630] [ 54.508644] CPU: 1 PID: 8330 Comm: syz-executor461 Not tainted 4.19.105-syzkaller #0 [ 54.508653] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.508658] Call Trace: [ 54.508677] dump_stack+0x197/0x210 [ 54.508694] ? con_shutdown+0x85/0x90 [ 54.508713] print_address_description.cold+0x7c/0x20d [ 54.508734] ? con_shutdown+0x85/0x90 [ 54.508748] kasan_report.cold+0x8c/0x2ba [ 54.508761] ? set_palette+0x1c0/0x1c0 [ 54.508779] __asan_report_store8_noabort+0x17/0x20 [ 54.508793] con_shutdown+0x85/0x90 [ 54.508808] release_tty+0xe4/0x4d0 [ 54.508823] tty_release_struct+0x3c/0x50 [ 54.508835] tty_release+0xbcb/0xe90 [ 54.508855] ? tty_release_struct+0x50/0x50 [ 54.508869] __fput+0x2dd/0x8b0 [ 54.508890] ____fput+0x16/0x20 [ 54.508904] task_work_run+0x145/0x1c0 [ 54.508929] do_exit+0xc1f/0x30d0 [ 54.508951] ? mm_update_next_owner+0x660/0x660 [ 54.508966] ? up_read+0x1a/0x110 [ 54.508980] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.508996] ? __do_page_fault+0x484/0xe90 [ 54.509018] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.509033] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.509050] do_group_exit+0x135/0x370 [ 54.509069] __x64_sys_exit_group+0x44/0x50 [ 54.509085] do_syscall_64+0xfd/0x620 [ 54.509106] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.509117] RIP: 0033:0x43ff38 [ 54.509131] 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 [ 54.509139] RSP: 002b:00007ffeec2d6838 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.509151] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 54.509159] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 54.509166] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.509173] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 54.509181] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 54.509199] [ 54.509205] Allocated by task 8330: [ 54.509218] save_stack+0x45/0xd0 [ 54.509228] kasan_kmalloc+0xce/0xf0 [ 54.509240] kmem_cache_alloc_trace+0x152/0x760 [ 54.509251] vc_allocate+0x1f5/0x760 [ 54.509264] con_install+0x52/0x410 [ 54.509275] tty_init_dev+0xf7/0x460 [ 54.509287] tty_open+0x4bf/0xb70 [ 54.509298] chrdev_open+0x245/0x6b0 [ 54.509308] do_dentry_open+0x4c3/0x1210 [ 54.509319] vfs_open+0xa0/0xd0 [ 54.509333] path_openat+0x10d8/0x44a0 [ 54.509347] do_filp_open+0x1a1/0x280 [ 54.509357] do_sys_open+0x3fe/0x550 [ 54.509368] __x64_sys_open+0x7e/0xc0 [ 54.509382] do_syscall_64+0xfd/0x620 [ 54.509395] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.509399] [ 54.509405] Freed by task 8332: [ 54.509417] save_stack+0x45/0xd0 [ 54.509429] __kasan_slab_free+0x102/0x150 [ 54.509441] kasan_slab_free+0xe/0x10 [ 54.509452] kfree+0xcf/0x220 [ 54.509474] vt_disallocate_all+0x2bd/0x3e0 [ 54.509488] vt_ioctl+0xc38/0x2530 [ 54.509500] tty_ioctl+0x7f3/0x1510 [ 54.509515] do_vfs_ioctl+0xd5f/0x1380 [ 54.509526] ksys_ioctl+0xab/0xd0 [ 54.509537] __x64_sys_ioctl+0x73/0xb0 [ 54.509550] do_syscall_64+0xfd/0x620 [ 54.509563] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.509567] [ 54.509577] The buggy address belongs to the object at ffff8880a8392100 [ 54.509577] which belongs to the cache kmalloc-2048 of size 2048 [ 54.509589] The buggy address is located 264 bytes inside of [ 54.509589] 2048-byte region [ffff8880a8392100, ffff8880a8392900) [ 54.509593] The buggy address belongs to the page: [ 54.509606] page:ffffea0002a0e480 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 [ 54.509620] flags: 0xfffe0000008100(slab|head) [ 54.509639] raw: 00fffe0000008100 ffffea0002228408 ffffea0002a18408 ffff88812c31cc40 [ 54.509654] raw: 0000000000000000 ffff8880a8392100 0000000100000003 0000000000000000 [ 54.509660] page dumped because: kasan: bad access detected [ 54.509664] [ 54.509668] Memory state around the buggy address: [ 54.509679] ffff8880a8392100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.509690] ffff8880a8392180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.509701] >ffff8880a8392200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.509705] ^ [ 54.509716] ffff8880a8392280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.509727] ffff8880a8392300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.509732] ================================================================== [ 54.509736] Disabling lock debugging due to kernel taint [ 54.513649] Kernel panic - not syncing: panic_on_warn set ... [ 54.513649] [ 54.513668] CPU: 1 PID: 8330 Comm: syz-executor461 Tainted: G B 4.19.105-syzkaller #0 [ 54.513676] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.513680] Call Trace: [ 54.513708] dump_stack+0x197/0x210 [ 54.513726] ? con_shutdown+0x85/0x90 [ 54.513744] panic+0x26a/0x50e [ 54.513760] ? __warn_printk+0xf3/0xf3 [ 54.513773] ? con_shutdown+0x85/0x90 [ 54.513790] ? preempt_schedule+0x4b/0x60 [ 54.513806] ? ___preempt_schedule+0x16/0x18 [ 54.513822] ? trace_hardirqs_on+0x5e/0x220 [ 54.513836] ? con_shutdown+0x85/0x90 [ 54.513852] kasan_end_report+0x47/0x4f [ 54.513866] kasan_report.cold+0xa9/0x2ba [ 54.513880] ? set_palette+0x1c0/0x1c0 [ 54.513895] __asan_report_store8_noabort+0x17/0x20 [ 54.513907] con_shutdown+0x85/0x90 [ 54.513921] release_tty+0xe4/0x4d0 [ 54.513935] tty_release_struct+0x3c/0x50 [ 54.513948] tty_release+0xbcb/0xe90 [ 54.513965] ? tty_release_struct+0x50/0x50 [ 54.513979] __fput+0x2dd/0x8b0 [ 54.513996] ____fput+0x16/0x20 [ 54.514010] task_work_run+0x145/0x1c0 [ 54.514025] do_exit+0xc1f/0x30d0 [ 54.514043] ? mm_update_next_owner+0x660/0x660 [ 54.514057] ? up_read+0x1a/0x110 [ 54.514072] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.514088] ? __do_page_fault+0x484/0xe90 [ 54.514104] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.514118] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.514133] do_group_exit+0x135/0x370 [ 54.514147] __x64_sys_exit_group+0x44/0x50 [ 54.514162] do_syscall_64+0xfd/0x620 [ 54.514180] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.514192] RIP: 0033:0x43ff38 [ 54.514205] 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 [ 54.514213] RSP: 002b:00007ffeec2d6838 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.514226] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 54.514233] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 54.514241] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.514248] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 54.514255] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 54.515857] Kernel Offset: disabled [ 55.213609] Rebooting in 86400 seconds..