Re: KASAN: stack-out-of-bounds Write in notify_die

[Dmitry Vyukov]

#syz dup: KASAN: use-after-free Read in do_general_protection

On Sat, May 26, 2018 at 11:13 AM, syzbot
<syzbot+cadaa9a49085b3cc83d3@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    203ec2fed17a Merge tag 'armsoc-fixes' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14feff97800000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f3b4e30da84ec1ed
> dashboard link: https://syzkaller.appspot.com/bug?extid=cadaa9a49085b3cc83d3
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+cadaa9a49085b3cc83d3@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ==================================================================
> BUG: KASAN: stack-out-of-bounds in notify_die+0x291/0x2b0
> kernel/notifier.c:539
> Write of size 8 at addr ffff8801c74d7258 by task syz-executor7/17787
>
> CPU: 1 PID: 17787 Comm: syz-executor7 Not tainted 4.17.0-rc5+ #60
> 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+0x1b9/0x294 lib/dump_stack.c:113
>  print_address_description+0x6c/0x20b mm/kasan/report.c:256
>  kasan_report_error mm/kasan/report.c:354 [inline]
>  kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
>  __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:438
>  notify_die+0x291/0x2b0 kernel/notifier.c:539
>  do_general_protection+0x248/0x2f0 arch/x86/kernel/traps.c:558
>  general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1159
> RIP: 0010:msr_write_intercepted arch/x86/kvm/vmx.c:2132 [inline]
> RIP: 0010:vmx_vcpu_run+0xa2f/0x25f0 arch/x86/kvm/vmx.c:9871
> RSP: 0018:ffff8801c74d73b0 EFLAGS: 00010006
> RAX: dffffc0000000000 RBX: 0000000010000000 RCX: ffffffff811f778f
> RDX: 000000000836b156 RSI: ffffffff811f779c RDI: 0000000000000005
> RBP: ffff8801c74d7898 R08: ffff8801ab74e140 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>
> The buggy address belongs to the page:
> page:ffffea00071d35c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
> flags: 0x2fffc0000000000()
> raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
> raw: 0000000000000000 ffffea00071d0101 0000000000000000 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffff8801c74d7100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  ffff8801c74d7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>>
>> ffff8801c74d7200: 00 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 f3 f3
>
>                                                     ^
>  ffff8801c74d7280: f3 f3 00 f2 f2 f2 f2 f2 f2 f2 00 00 f2 f2 f3 f3
>  ffff8801c74d7300: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ==================================================================
>
>
> ---
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