audit: type=1400 audit(1581255803.640:36): avc: denied { map } for pid=7230 comm="syz-executor228" path="/root/syz-executor228633445" 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 ================================================================== BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:2930 Write of size 8 at addr ffff8880997e5208 by task syz-executor228/7237 CPU: 0 PID: 7237 Comm: syz-executor228 Not tainted 4.14.170-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435 con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:2930 release_tty+0xbf/0x7c0 drivers/tty/tty_io.c:1501 tty_release_struct+0x3c/0x50 drivers/tty/tty_io.c:1616 tty_release+0xaa3/0xd60 drivers/tty/tty_io.c:1776 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa1a/0x2cd0 kernel/exit.c:858 do_group_exit+0x111/0x330 kernel/exit.c:955 SYSC_exit_group kernel/exit.c:966 [inline] SyS_exit_group+0x1d/0x20 kernel/exit.c:964 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x43ff38 RSP: 002b:00007ffefce928b8 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 7237: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kmem_cache_alloc_trace+0x152/0x790 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] kzalloc include/linux/slab.h:661 [inline] vc_allocate drivers/tty/vt/vt.c:772 [inline] vc_allocate+0x148/0x580 drivers/tty/vt/vt.c:753 con_install+0x52/0x400 drivers/tty/vt/vt.c:2881 tty_driver_install_tty drivers/tty/tty_io.c:1225 [inline] tty_init_dev drivers/tty/tty_io.c:1338 [inline] tty_init_dev+0xea/0x3a0 drivers/tty/tty_io.c:1315 tty_open_by_driver drivers/tty/tty_io.c:1973 [inline] tty_open+0x414/0xa10 drivers/tty/tty_io.c:2021 chrdev_open+0x207/0x590 fs/char_dev.c:423 do_dentry_open+0x73b/0xeb0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:891 do_last fs/namei.c:3428 [inline] path_openat+0x917/0x3e50 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x2c5/0x430 fs/open.c:1084 SYSC_open fs/open.c:1102 [inline] SyS_open+0x2d/0x40 fs/open.c:1097 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 7238: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 vt_disallocate_all+0x286/0x380 drivers/tty/vt/vt_ioctl.c:323 vt_ioctl+0x76b/0x2170 drivers/tty/vt/vt_ioctl.c:816 tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8880997e5100 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 264 bytes inside of 2048-byte region [ffff8880997e5100, ffff8880997e5900) The buggy address belongs to the page: page:ffffea000265f900 count:1 mapcount:0 mapping:ffff8880997e4000 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff8880997e4000 0000000000000000 0000000100000003 raw: ffffea000264c4a0 ffffea00026430a0 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880997e5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880997e5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880997e5200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880997e5280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880997e5300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================