Re: [PATCH 00/12] x86/CET: The last 12 patches to enable Intel CET

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, Jul 27, 2018 at 10:52 AM, Florian Weimer <fweimer@redhat.com> wrote:
> On 07/27/2018 07:50 PM, H.J. Lu wrote:
>>
>> On Fri, Jul 27, 2018 at 10:13 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>
>>> On Fri, Jul 27, 2018 at 9:49 AM, Florian Weimer <fweimer@redhat.com>
>>> wrote:
>>>>
>>>> On 07/27/2018 06:47 PM, H.J. Lu wrote:
>>>>>
>>>>>
>>>>> On Fri, Jul 27, 2018 at 9:44 AM, Florian Weimer <fweimer@redhat.com>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> On 07/27/2018 06:37 PM, H.J. Lu wrote:
>>>>>>
>>>>>>>> We load datasz and then check for having encountered the last note.
>>>>>>>> I'm
>>>>>>>> checking a fix.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> How can I reproduce it?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Perhaps it is only visible with an explicit invocation of the dynamic
>>>>>> linker?
>>>>>>
>>>>>> I saw it while building GCC on Fedora rawhide.  I've pushed my latest
>>>>>> changes (commit a4a5659439698554d18b9f1ef56cbd86591e217b) to the
>>>>>> distribution Git, even though they do not build.  The valgrind check
>>>>>> at
>>>>>> the
>>>>>> end of the build fails.
>>>>>
>>>>>
>>>>>
>>>>> What is the command line to reproduce it with glibc build configured
>>>>> with --enable-cet?
>>>>
>>>>
>>>>
>>>> This command is run inside the build directory:
>>>>
>>>> elf/ld.so --library-path .:elf:nptl:dlfcn /usr/bin/valgrind
>>>> --vgdb-error=1
>>>> --track-origins=yes --error-exitcode=1 elf/ld.so --library-path
>>>> .:elf:nptl:dlfcn /usr/bin/true
>>>>
>>>
>>> [hjl@gnu-cet-2 build-x86_64-linux]$ elf/ld.so --library-path
>>> .:elf:nptl:dlfcn /usr/bin/valgrind --vgdb-error=1 --track-origins=yes
>>> --error-exitcode=1 elf/ld.so --library-path .:elf:nptl:dlfcn
>>> /usr/bin/true
>>>
>>
>> Your note may be different.  Mine has
>>
>> [hjl@gnu-cet-1 build-x86_64-linux]$ readelf -n elf/ld.so
>>
>> Displaying notes found in: .note.gnu.build-id
>>    Owner                 Data size Description
>>    GNU                  0x00000014 NT_GNU_BUILD_ID (unique build ID
>> bitstring)
>>      Build ID: 47063ae06339e7226b68aa983cd3225f2dfa1ee2
>>
>> Displaying notes found in: .note.gnu.property
>>    Owner                 Data size Description
>>    GNU                  0x00000010 NT_GNU_PROPERTY_TYPE_0
>>        Properties: x86 feature: IBT, SHSTK
>> [hjl@gnu-cet-1 build-x86_64-linux]$
>>
>> Can you send me your elf/ld.so?
>
>
> The note for /bin/true causes the problem.  I'm attaching it.
>

Yes, I can reproduce it.  Let me take a look.

-- 
H.J.