audit: type=1400 audit(1581252640.321:36): avc: denied { map } for pid=8020 comm="syz-executor681" path="/root/syz-executor681324337" dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ================================================================== BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:3253 Write of size 8 at addr ffff88808eb9f548 by task syz-executor681/8028 CPU: 0 PID: 8028 Comm: syz-executor681 Not tainted 4.19.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:438 con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:3253 release_tty+0xe4/0x4d0 drivers/tty/tty_io.c:1509 tty_release_struct+0x3c/0x50 drivers/tty/tty_io.c:1624 tty_release+0xbcb/0xe90 drivers/tty/tty_io.c:1784 __fput+0x2dd/0x8b0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xc1f/0x30d0 kernel/exit.c:880 do_group_exit+0x135/0x370 kernel/exit.c:983 __do_sys_exit_group kernel/exit.c:994 [inline] __se_sys_exit_group kernel/exit.c:992 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:992 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x43ff38 Code: Bad RIP value. RSP: 002b:00007ffd081b84d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 8028: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] vc_allocate drivers/tty/vt/vt.c:1088 [inline] vc_allocate+0x1f5/0x760 drivers/tty/vt/vt.c:1069 con_install+0x52/0x410 drivers/tty/vt/vt.c:3204 tty_driver_install_tty drivers/tty/tty_io.c:1226 [inline] tty_init_dev drivers/tty/tty_io.c:1339 [inline] tty_init_dev+0xf7/0x460 drivers/tty/tty_io.c:1316 tty_open_by_driver drivers/tty/tty_io.c:1981 [inline] tty_open+0x4bf/0xb70 drivers/tty/tty_io.c:2029 chrdev_open+0x245/0x6b0 fs/char_dev.c:423 do_dentry_open+0x4c3/0x1210 fs/open.c:796 vfs_open+0xa0/0xd0 fs/open.c:905 do_last fs/namei.c:3421 [inline] path_openat+0x10d8/0x44a0 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x550 fs/open.c:1088 __do_sys_open fs/open.c:1106 [inline] __se_sys_open fs/open.c:1101 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1101 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8030: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 vt_disallocate_all+0x2bd/0x3e0 drivers/tty/vt/vt_ioctl.c:323 vt_ioctl+0xc38/0x2530 drivers/tty/vt/vt_ioctl.c:816 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88808eb9f440 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 264 bytes inside of 2048-byte region [ffff88808eb9f440, ffff88808eb9fc40) The buggy address belongs to the page: page:ffffea00023ae780 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea0001ffb088 ffffea0002579708 ffff88812c31cc40 raw: 0000000000000000 ffff88808eb9e340 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808eb9f400: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff88808eb9f480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808eb9f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808eb9f580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808eb9f600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================