[cfe-dev] stack overflow detection?

[Kostya Serebryany]

On Wed, Sep 18, 2013 at 12:30 PM, Chandler Carruth <chandlerc at google.com>wrote:

>
> On Wed, Sep 18, 2013 at 1:19 AM, Kostya Serebryany <kcc at google.com> wrote:
>
>> This can be solved with sigaltstack() and AddressSanitizer does this
>> under a separate
>> (experimental) flag ASAN_OPTIONS=use_sigaltstack=1
>>
>
> Is there a bug tracking what is needed to enable this by default? Might be
> a nice project for folks that want to improve support for this situation.
>

Not that I know of. There will be users who would not like this by default.
sigaltstack in asan is not cheap -- it currently costs 32K RAM per thread.
We have users with default 64K per thread stack and they set this strict
limit for a good reason -- they have thousands of threads.
So, adding 50% to their stack size is not great.
remember that sigaltstack does not help to detect any new bugs -- it just
makes the SEGV a bit more verbose.

Having said that, I am actually not opposed to setting use_sigaltstack=1 by
default.
It's just that we didn't spend much time evaluating it.

--kcc
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