linux-kernel - Re: [PATCH 0/5] Collected vdso/vsyscall fixes for 3.1

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Date:	Wed, 27 Jul 2011 11:34:21 -0400
From:	Andrew Lutomirski <luto@....edu>
To:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:	x86@...nel.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	jeremy@...p.org, keir.xen@...il.com, xen-devel@...ts.xensource.com,
	virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 0/5] Collected vdso/vsyscall fixes for 3.1

On Wed, Jul 27, 2011 at 11:30 AM, Konrad Rzeszutek Wilk
<konrad.wilk@...cle.com> wrote:
>> > Anyhow, removed the benchmark code and ran it on 64-bit:
>> >
>> > sh-4.1# /test_vsyscall  test
>> > Testing gettimeofday...
>> > [  109.552261] test_vsyscall[2462] trap invalid opcode ip:400c8d sp:7fff84fab470 error:0 in test_vsyscall[400000+2000]
>> > Illegal instruction
>> > sh-4.1# /test_vsyscall  intcc
>> > About to execute int 0xcc from RIP = 400959
>> > [  114.137150] test_vsyscall[2463] illegal int 0xcc (exploit attempt?) ip:400959 cs:e033 sp:7fff8b328310 ax:2c si:0 di:7fff8b3280f0
>> > Caught SIGSEGV: Segmentation fault (Signal sent by the kernel [(nil)])RIP = 400959
>> >
>> > [This is on git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git #testing, which
>> > has todays linus/master and your patchset]
>> >
>>
>> I'll set up Xen.  Something's clearly still buggy.
>
> You sure? This is what I get when I boot baremetal:
>
> sh-4.1#
> sh-4.1# xen-detect
> Not running on Xen.
> sh-4.1# /test_vsyscall test
> Testing gettimeo[   84.442819] test_vsyscall[3175] trap invalid opcode ip:400c8d sp:7fffa8a72dc0 error:0fday...
>  in test_vsyscall[400000+2000]

$ test_vsyscall test
Testing gettimeofday...
  vDSO offset = 0.000001s
  vsyscall offset = 0.000001s

Testing time...
  vDSO offset = 0
  vsyscall offset = 0
Testing getcpu...
  ok!  cpu=6 node=0

Can you send me your test_vsyscall binary so I can disassemble it?

--Andy
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