* KASAN: out-of-bounds Write in nested_sync_vmcs12_to_shadow
@ 2020-04-21 0:15 syzbot
2020-04-21 13:38 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2020-04-21 0:15 UTC (permalink / raw)
To: bp, hpa, jmattson, joro, kvm, linux-kernel, mingo, pbonzini,
sean.j.christopherson, syzkaller-bugs, tglx, vkuznets, wanpengli,
x86
Hello,
syzbot found the following crash on:
HEAD commit: 9786cab6 Merge tag 'selinux-pr-20200416' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1110c920100000
kernel config: https://syzkaller.appspot.com/x/.config?x=5d351a1019ed81a2
dashboard link: https://syzkaller.appspot.com/bug?extid=6ad11779184a3afe9f7e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=141f46abe00000
Bisection is inconclusive: the bug happens on the oldest tested release.
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12b44c73e00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=11b44c73e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=16b44c73e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6ad11779184a3afe9f7e@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: out-of-bounds in copy_vmcs12_to_enlightened arch/x86/kvm/vmx/nested.c:1820 [inline]
BUG: KASAN: out-of-bounds in nested_sync_vmcs12_to_shadow+0x49e3/0x4a60 arch/x86/kvm/vmx/nested.c:2000
Write of size 2 at addr ffffc90004db72e8 by task syz-executor.4/8294
CPU: 1 PID: 8294 Comm: syz-executor.4 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x188/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0x5/0x315 mm/kasan/report.c:382
__kasan_report.cold+0x35/0x4d mm/kasan/report.c:511
kasan_report+0x33/0x50 mm/kasan/common.c:625
copy_vmcs12_to_enlightened arch/x86/kvm/vmx/nested.c:1820 [inline]
nested_sync_vmcs12_to_shadow+0x49e3/0x4a60 arch/x86/kvm/vmx/nested.c:2000
</IRQ>
Memory state around the buggy address:
ffffc90004db7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc90004db7200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004db7280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffffc90004db7300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc90004db7380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: KASAN: out-of-bounds Write in nested_sync_vmcs12_to_shadow
2020-04-21 0:15 KASAN: out-of-bounds Write in nested_sync_vmcs12_to_shadow syzbot
@ 2020-04-21 13:38 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2020-04-21 13:38 UTC (permalink / raw)
To: syzbot, bp, hpa, jmattson, joro, kvm, linux-kernel, mingo,
sean.j.christopherson, syzkaller-bugs, tglx, vkuznets, wanpengli,
x86
On 21/04/20 02:15, syzbot wrote:
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+6ad11779184a3afe9f7e@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: out-of-bounds in copy_vmcs12_to_enlightened arch/x86/kvm/vmx/nested.c:1820 [inline]
> BUG: KASAN: out-of-bounds in nested_sync_vmcs12_to_shadow+0x49e3/0x4a60 arch/x86/kvm/vmx/nested.c:2000
> Write of size 2 at addr ffffc90004db72e8 by task syz-executor.4/8294
>
> CPU: 1 PID: 8294 Comm: syz-executor.4 Not tainted 5.7.0-rc1-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> <IRQ>
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x188/0x20d lib/dump_stack.c:118
> print_address_description.constprop.0.cold+0x5/0x315 mm/kasan/report.c:382
> __kasan_report.cold+0x35/0x4d mm/kasan/report.c:511
> kasan_report+0x33/0x50 mm/kasan/common.c:625
> copy_vmcs12_to_enlightened arch/x86/kvm/vmx/nested.c:1820 [inline]
> nested_sync_vmcs12_to_shadow+0x49e3/0x4a60 arch/x86/kvm/vmx/nested.c:2000
> </IRQ>
That's a weird stack trace for a reproducer that is doing operations on
/dev/fb0. What's going on?
Paolo
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2020-04-21 13:38 ` Paolo Bonzini
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