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


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.

Thanks,
Florian

Attachment: true
Description: Binary data


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