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

[Nick Alcock <nix at esperi dot org dot uk>]

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...