================================================================== BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:3278 Write of size 8 at addr ffff8880a4a38108 by task syz-executor.5/30035 CPU: 0 PID: 30035 Comm: syz-executor.5 Not tainted 5.5.0-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.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:140 con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:3278 release_tty+0xd3/0x470 drivers/tty/tty_io.c:1514 tty_release_struct+0x3c/0x50 drivers/tty/tty_io.c:1629 tty_release+0xbcb/0xe90 drivers/tty/tty_io.c:1789 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 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+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x414f31 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:00007ffd3a313db0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000414f31 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000001 R08: 00000000d86272b8 R09: 00000000d86272bc R10: 00007ffd3a313e90 R11: 0000000000000293 R12: 000000000075bf20 R13: 000000000024d011 R14: 00000000007601e8 R15: 000000000075bf2c Allocated by task 29466: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] vc_allocate drivers/tty/vt/vt.c:1085 [inline] vc_allocate+0x1fc/0x760 drivers/tty/vt/vt.c:1066 con_install+0x52/0x410 drivers/tty/vt/vt.c:3229 tty_driver_install_tty drivers/tty/tty_io.c:1228 [inline] tty_init_dev drivers/tty/tty_io.c:1341 [inline] tty_init_dev+0xf9/0x470 drivers/tty/tty_io.c:1318 tty_open_by_driver drivers/tty/tty_io.c:1987 [inline] tty_open+0x4a5/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3490 [inline] path_openat+0x12ee/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 ksys_open include/linux/syscalls.h:1386 [inline] __do_sys_open fs/open.c:1171 [inline] __se_sys_open fs/open.c:1169 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1169 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 30036: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 vt_disallocate_all+0x2bd/0x3e0 drivers/tty/vt/vt_ioctl.c:323 vt_ioctl+0xc38/0x26d0 drivers/tty/vt/vt_ioctl.c:816 tty_ioctl+0xa37/0x14f0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x123/0x180 fs/ioctl.c:747 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a4a38000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 264 bytes inside of 2048-byte region [ffff8880a4a38000, ffff8880a4a38800) The buggy address belongs to the page: page:ffffea0002928e00 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00029e3348 ffffea00023f9508 ffff8880aa400e00 raw: 0000000000000000 ffff8880a4a38000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a4a38000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a4a38080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a4a38100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a4a38180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a4a38200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================