audit: type=1400 audit(1575378425.568:36): avc: denied { map } for pid=7077 comm="syz-executor250" path="/root/syz-executor250097564" 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 ================================================================== BUG: KASAN: use-after-free in constant_test_bit arch/x86/include/asm/bitops.h:325 [inline] BUG: KASAN: use-after-free in tty_port_kopened include/linux/tty.h:664 [inline] BUG: KASAN: use-after-free in tty_open_by_driver drivers/tty/tty_io.c:1952 [inline] BUG: KASAN: use-after-free in tty_open+0x995/0xa10 drivers/tty/tty_io.c:2021 Read of size 8 at addr ffff88807555e480 by task syz-executor250/7091 CPU: 1 PID: 7091 Comm: syz-executor250 Not tainted 4.14.157-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_load8_noabort+0x14/0x20 mm/kasan/report.c:430 constant_test_bit arch/x86/include/asm/bitops.h:325 [inline] tty_port_kopened include/linux/tty.h:664 [inline] tty_open_by_driver drivers/tty/tty_io.c:1952 [inline] tty_open+0x995/0xa10 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:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 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 RIP: 0033:0x401140 RSP: 002b:00007fff817f6a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000401140 RDX: 0000000000000000 RSI: 0000000000127200 RDI: 00007fff817f6aa0 RBP: 000000000000a57f R08: 000000000000000f R09: 00000000004002e0 R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402160 R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 7086: 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:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 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 7091: 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 ffff88807555e280 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 512 bytes inside of 2048-byte region [ffff88807555e280, ffff88807555ea80) The buggy address belongs to the page: page:ffffea0001d55780 count:1 mapcount:0 mapping:ffff88807555e280 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff88807555e280 0000000000000000 0000000100000003 raw: ffffea000233b5a0 ffffea0002a17720 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807555e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807555e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807555e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807555e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807555e580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================