==================================================================
BUG: KASAN: use-after-free in con_shutdown+0x76/0x80 drivers/tty/vt/vt.c:3278
Write of size 8 at addr ffff88808f207108 by task syz-executor.5/15884

CPU: 0 PID: 15884 Comm: syz-executor.5 Not tainted 5.5.0-rc7-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+0x12d/0x187 lib/dump_stack.c:118
 print_address_description.constprop.8.cold.10+0x9/0x31d mm/kasan/report.c:374
 __kasan_report.cold.11+0x1b/0x3a mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:140
 con_shutdown+0x76/0x80 drivers/tty/vt/vt.c:3278
 release_tty+0xa6/0x400 drivers/tty/tty_io.c:1514
 tty_release_struct+0x33/0x50 drivers/tty/tty_io.c:1629
 tty_release+0x97e/0xc60 drivers/tty/tty_io.c:1789
 __fput+0x25a/0x770 fs/file_table.c:280
 ____fput+0x9/0x10 fs/file_table.c:313
 task_work_run+0x108/0x180 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x24e/0x2e0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x4ff/0x5f0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4144a1
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fff15f17430 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00000000004144a1
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000001 R08: ffffffffffffffff R09: ffffffffffffffff
R10: 00007fff15f17510 R11: 0000000000000293 R12: 000000000075bf20
R13: 0000000000018f10 R14: 0000000000760320 R15: 000000000075bf2c

Allocated by task 7887:
 save_stack+0x21/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc.constprop.17+0xc7/0xd0 mm/kasan/common.c:513
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 kmem_cache_alloc_trace+0x15b/0x780 mm/slab.c:3551
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:670 [inline]
 vc_allocate+0x1b7/0x7c0 drivers/tty/vt/vt.c:1085
 con_install+0x4d/0x410 drivers/tty/vt/vt.c:3229
 tty_driver_install_tty drivers/tty/tty_io.c:1228 [inline]
 tty_init_dev+0xda/0x3c0 drivers/tty/tty_io.c:1341
 tty_open_by_driver drivers/tty/tty_io.c:1987 [inline]
 tty_open+0x514/0x9f0 drivers/tty/tty_io.c:2035
 chrdev_open+0x1ed/0x5c0 fs/char_dev.c:414
 do_dentry_open+0x3fa/0x1100 fs/open.c:797
 vfs_open+0x9a/0xc0 fs/open.c:914
 do_last fs/namei.c:3359 [inline]
 path_openat+0x847/0x2d90 fs/namei.c:3476
 do_filp_open+0x177/0x250 fs/namei.c:3506
 do_sys_open+0x1dd/0x370 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x79/0xb0 fs/open.c:1110
 do_syscall_64+0xca/0x5f0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 15889:
 save_stack+0x21/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x108/0x2c0 mm/slab.c:3757
 vt_disallocate_all+0x247/0x3f0 drivers/tty/vt/vt_ioctl.c:323
 vt_ioctl+0x18c6/0x21f0 drivers/tty/vt/vt_ioctl.c:816
 tty_ioctl+0x45b/0x12f0 drivers/tty/tty_io.c:2660
 vfs_ioctl fs/ioctl.c:47 [inline]
 file_ioctl fs/ioctl.c:545 [inline]
 do_vfs_ioctl+0x196/0x1190 fs/ioctl.c:732
 ksys_ioctl+0x62/0x90 fs/ioctl.c:749
 __do_sys_ioctl fs/ioctl.c:756 [inline]
 __se_sys_ioctl fs/ioctl.c:754 [inline]
 __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:754
 do_syscall_64+0xca/0x5f0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808f207000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 264 bytes inside of
 2048-byte region [ffff88808f207000, ffff88808f207800)
The buggy address belongs to the page:
page:ffffea00023c81c0 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0
raw: 00fffe0000000200 ffffea000272fb88 ffffea0002590348 ffff8880aa400e00
raw: 0000000000000000 ffff88808f207000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808f207000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808f207080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808f207100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88808f207180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808f207200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================