[ 43.564029] audit: type=1800 audit(1581306019.175:30): pid=7925 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 syzkaller login: [ 47.453182] kauditd_printk_skb: 4 callbacks suppressed [ 47.453198] audit: type=1400 audit(1581306023.105:35): avc: denied { map } for pid=8098 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 '10.128.0.20' (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 executing program [ 54.347712] audit: type=1400 audit(1581306030.005:36): avc: denied { map } for pid=8110 comm="syz-executor791" path="/root/syz-executor791979760" dev="sda1" ino=16483 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 54.590294] ================================================================== [ 54.590331] BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 [ 54.590341] Write of size 8 at addr ffff888093d81388 by task syz-executor791/8144 [ 54.590345] [ 54.590359] CPU: 0 PID: 8144 Comm: syz-executor791 Not tainted 4.19.102-syzkaller #0 [ 54.590367] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.590372] Call Trace: [ 54.590390] dump_stack+0x197/0x210 [ 54.590409] ? con_shutdown+0x85/0x90 [ 54.590426] print_address_description.cold+0x7c/0x20d [ 54.590442] ? con_shutdown+0x85/0x90 [ 54.590458] kasan_report.cold+0x8c/0x2ba [ 54.590474] ? set_palette+0x1c0/0x1c0 [ 54.590492] __asan_report_store8_noabort+0x17/0x20 [ 54.590506] con_shutdown+0x85/0x90 [ 54.590520] release_tty+0xe4/0x4d0 [ 54.590538] tty_release_struct+0x3c/0x50 [ 54.590553] tty_release+0xbcb/0xe90 [ 54.590577] ? tty_release_struct+0x50/0x50 [ 54.590591] __fput+0x2dd/0x8b0 [ 54.590614] ____fput+0x16/0x20 [ 54.590628] task_work_run+0x145/0x1c0 [ 54.590648] do_exit+0xc1f/0x30d0 [ 54.590681] ? mm_update_next_owner+0x660/0x660 [ 54.590696] ? up_read+0x1a/0x110 [ 54.590710] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.590725] ? __do_page_fault+0x484/0xe90 [ 54.590747] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.590763] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.590781] do_group_exit+0x135/0x370 [ 54.590800] __x64_sys_exit_group+0x44/0x50 [ 54.590815] do_syscall_64+0xfd/0x620 [ 54.590842] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.590854] RIP: 0033:0x43ff38 [ 54.590868] 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 [ 54.590876] RSP: 002b:00007ffd33dbf2e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.590890] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 54.590898] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 54.590907] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.590915] R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001 [ 54.590923] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 54.590942] [ 54.590949] Allocated by task 8144: [ 54.590962] save_stack+0x45/0xd0 [ 54.590974] kasan_kmalloc+0xce/0xf0 [ 54.590987] kmem_cache_alloc_trace+0x152/0x760 [ 54.590999] vc_allocate+0x1f5/0x760 [ 54.591013] con_install+0x52/0x410 [ 54.591024] tty_init_dev+0xf7/0x460 [ 54.591036] tty_open+0x4bf/0xb70 [ 54.591047] chrdev_open+0x245/0x6b0 [ 54.591057] do_dentry_open+0x4c3/0x1210 [ 54.591067] vfs_open+0xa0/0xd0 [ 54.591082] path_openat+0x10d8/0x44a0 [ 54.591091] do_filp_open+0x1a1/0x280 [ 54.591101] do_sys_open+0x3fe/0x550 [ 54.591112] __x64_sys_open+0x7e/0xc0 [ 54.591125] do_syscall_64+0xfd/0x620 [ 54.591140] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.591144] [ 54.591150] Freed by task 8149: [ 54.591163] save_stack+0x45/0xd0 [ 54.591176] __kasan_slab_free+0x102/0x150 [ 54.591189] kasan_slab_free+0xe/0x10 [ 54.591200] kfree+0xcf/0x220 [ 54.591215] vt_disallocate_all+0x2bd/0x3e0 [ 54.591229] vt_ioctl+0xc38/0x2530 [ 54.591241] tty_ioctl+0x7f3/0x1510 [ 54.591254] do_vfs_ioctl+0xd5f/0x1380 [ 54.591266] ksys_ioctl+0xab/0xd0 [ 54.591278] __x64_sys_ioctl+0x73/0xb0 [ 54.591291] do_syscall_64+0xfd/0x620 [ 54.591305] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.591309] [ 54.591319] The buggy address belongs to the object at ffff888093d81280 [ 54.591319] which belongs to the cache kmalloc-2048 of size 2048 [ 54.591331] The buggy address is located 264 bytes inside of [ 54.591331] 2048-byte region [ffff888093d81280, ffff888093d81a80) [ 54.591335] The buggy address belongs to the page: [ 54.591346] page:ffffea00024f6000 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 [ 54.591360] flags: 0xfffe0000008100(slab|head) [ 54.591378] raw: 00fffe0000008100 ffffea0002569288 ffffea00021b0388 ffff88812c31cc40 [ 54.591394] raw: 0000000000000000 ffff888093d80180 0000000100000003 0000000000000000 [ 54.591400] page dumped because: kasan: bad access detected [ 54.591403] [ 54.591408] Memory state around the buggy address: [ 54.591419] ffff888093d81280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.591430] ffff888093d81300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.591441] >ffff888093d81380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.591445] ^ [ 54.591456] ffff888093d81400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.591467] ffff888093d81480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 54.591472] ================================================================== [ 54.591476] Disabling lock debugging due to kernel taint [ 54.591877] Kernel panic - not syncing: panic_on_warn set ... [ 54.591877] [ 54.591889] CPU: 0 PID: 8144 Comm: syz-executor791 Tainted: G B 4.19.102-syzkaller #0 [ 54.591894] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.591897] Call Trace: [ 54.591911] dump_stack+0x197/0x210 [ 54.591924] ? con_shutdown+0x85/0x90 [ 54.591935] panic+0x26a/0x50e [ 54.591947] ? __warn_printk+0xf3/0xf3 [ 54.591959] ? con_shutdown+0x85/0x90 [ 54.591968] ? preempt_schedule+0x4b/0x60 [ 54.591982] ? ___preempt_schedule+0x16/0x18 [ 54.591996] ? trace_hardirqs_on+0x5e/0x220 [ 54.592011] ? con_shutdown+0x85/0x90 [ 54.592025] kasan_end_report+0x47/0x4f [ 54.592039] kasan_report.cold+0xa9/0x2ba [ 54.592053] ? set_palette+0x1c0/0x1c0 [ 54.592069] __asan_report_store8_noabort+0x17/0x20 [ 54.592082] con_shutdown+0x85/0x90 [ 54.592094] release_tty+0xe4/0x4d0 [ 54.592108] tty_release_struct+0x3c/0x50 [ 54.592119] tty_release+0xbcb/0xe90 [ 54.592136] ? tty_release_struct+0x50/0x50 [ 54.592149] __fput+0x2dd/0x8b0 [ 54.592165] ____fput+0x16/0x20 [ 54.592177] task_work_run+0x145/0x1c0 [ 54.592193] do_exit+0xc1f/0x30d0 [ 54.592211] ? mm_update_next_owner+0x660/0x660 [ 54.592223] ? up_read+0x1a/0x110 [ 54.592236] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.592249] ? __do_page_fault+0x484/0xe90 [ 54.592266] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.592281] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.592296] do_group_exit+0x135/0x370 [ 54.592309] __x64_sys_exit_group+0x44/0x50 [ 54.592320] do_syscall_64+0xfd/0x620 [ 54.592332] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.592339] RIP: 0033:0x43ff38 [ 54.592351] Code: Bad RIP value. [ 54.592356] RSP: 002b:00007ffd33dbf2e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.592365] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 54.592371] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 54.592377] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.592383] R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001 [ 54.592388] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 54.593594] Kernel Offset: disabled [ 55.264869] Rebooting in 86400 seconds..