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

[Florian Weimer <fweimer at redhat dot com>]

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