[PATCH] Remove debug/stack_chk_fail_local.c [BZ #21740]

[H.J. Lu]

On Mon, Jul 10, 2017 at 6:29 AM, Nick Alcock <nix@esperi.org.uk> wrote:
> On 10 Jul 2017, H. J. Lu said:
>> On Mon, Jul 10, 2017 at 11:50:02AM +0100, Nick Alcock wrote:
>>> If it passes a test build with --enable-stack-protector=all without
>>> pulling junk into ld.so and exploding at ld.so link time, sure. (That's
>>> what happened every time I tried to remove this stuff before, but I may
>>> have failed to notice that this may not be necessary any more.)
>>
>> Here is the updated patch.  tst-_dl_addr_inside_object should be
>> linked with $(dummy-stack-chk-fail).  Otherwise, __stack_chk_fail is
>> undefined.  OK for master branch?
>
> I presume this is because it's in $(all-nonlib)? Are other all-nonlib
> things similarly affected? (If they are, is the code in Makerules
> perhaps a better place to adjust this?)
>
> I guess the only affected nonlib things would be things that directly
> link against objects that will otherwise end up in the shared libc or
> ld.so, which means this is the only affected test (since only those
> things reference the usually-hidden __stack_chk_fail). If so, I have no
> objection to this patch, but maybe a comment explaining this would be a
> good idea so that if more such tests turn up in future this unusual
> piece of linking can be generalized a bit.
>
> Modulo that, I have no objections, but of course I also have no actual
> right to ack anything whatsoever :)
>
>>> > -/* On some architectures, this helps needless PIC pointer setup
>>> > -   that would be needed just for the __stack_chk_fail call.  */
>>>
>>> Does anyone know what architectures these might be? Presumably x86-32...
>>>
>>
>> config/i386/i386.c:   __stack_chk_fail_local hidden function instead of calling
>
> I presume you tested a build on x86-32 :) I guess that will suffice...

We must keep debug/stack_chk_fail_local.c for libc_nonshared.a.
Here is the updated patch to add __stack_chk_fail_local alias only
to libc.so.

Tested on i686 and x86-64 with and without --enable-stack-protector=all.
OK for master?


-- 
H.J.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Add-__stack_chk_fail_local-alias-only-to-libc.so-BZ-.patch
Type: text/x-patch
Size: 1598 bytes
Desc: not available
URL: <http://sourceware.org/pipermail/libc-alpha/attachments/20170710/0215aee5/attachment.bin>