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Re: [PATCH v2 0/3] Mips support for PT_GNU_STACK
- From: Faraz Shahbazker <fshahbazker at wavecomp dot com>
- To: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>, Dragan Mladjenovic <dmladjenovic at wavecomp dot com>, "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Cc: Joseph Myers <joseph at codesourcery dot com>, Carlos O'Donell <carlos at redhat dot com>, "Maciej W . Rozycki" <macro at linux-mips dot org>
- Date: Thu, 18 Jul 2019 15:34:11 +0000
- Subject: Re: [PATCH v2 0/3] Mips support for PT_GNU_STACK
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- References: <1563214941-16203-1-git-send-email-dmladjenovic@wavecomp.com> <a21dabcc-4f24-8d74-08c6-3ee57b3df2bb@linaro.org> <afa259cf-4f4d-a492-996e-dbdc2fabbb37@wavecomp.com> <e5641987-f618-0a51-0bd8-ef56efa0b23a@linaro.org>
On 7/18/19 6:38 AM, Adhemerval Zanella wrote:> On 17/07/2019 19:59, Faraz Shahbazker wrote:
>> On 07/17/2019 12:43 PM, Adhemerval Zanella wrote:
>> IMO, the current behaviour of PT_GNU_STACK for MIPS is an anomaly in itself. What should
>> have been, is a rejection of non-executable PT_GNU_STACK at some level, instead of silently
>> overriding it in glibc. So are you of the opinion that this change in glibc behaviour is not
>> worth being published at all, or that it should be advertised using a different mechanism
>> instead of an ABI version bump?
>
> Since non-executable stack is tied with underlying kernel support rather than
> ABI, my suggestion is just to assume non-executable stack as default, without
> permission override, if glibc is configure for kernel higher than *4.8*. We will
> need to live with old behaviour for default builds.
Frankly, I can live with that. If someone really wants to back-port they have to do the
leg-work across multiple components to get it to work. This theoretically still leaves
the door open for the kernel to start advertising non-exec stack support to allow for
easier back-ports.
Regards,
Faraz