[PATCH] pthread_detach: add a comment about a known segfault bug.

[Carlos O'Donell]

On 11/24/25 5:25 PM, Aaron Jacobs wrote:
> On Tue, Nov 25, 2025 at 1:06 AM Adhemerval Zanella Netto
> <adhemerval.zanella@linaro.org> wrote:
>> And I do not think adding a comment to bug report improves much here. We
>> already have a bug report with a lot of background, and a proposed solution.
> 
> Right, but the bug report is not discoverable from the source code, which
> somebody like me may spend hours looking at before luckily finding the bug
> report from some random Reddit thread when they finally get the right search
> term. This is not a good experience.

The 4th hit in google for "pthread_detach known segfault" is bug 19951.

> This also happened to the other very experienced engineer with lots of
> debugging experience in glibc and elsewhere who was assisting me.
> 
> What is the harm of making it more discoverable? This can easily be reverted
> with the fix for the bug.

There is no objective harm in making it more discoverable.

We have in the past documented known issues in the sources with links to bugs.

The point Adhmerveral makes is that we could just review the fix?

It's a matter of taste here, to put effort into the fix.

If we get close to the release without a fix, then we should put in some comments.

  
> On Tue, Nov 25, 2025 at 2:21 AM Sam James <sam@gentoo.org> wrote:
>> If you can test azanella's patches in an environment where you can
>> reliably reproduce the bug, that would be very helpful indeed.
> 
> Will do if/when I figure out how to wrangle our build system to let me use
> local edits to glibc. But I've also attached a test that reproduces the
> problem once every few thousand runs, at least when run on Google's
> distributed test running system.
> 
> (It uses Google-isms, but all open source stuff, and all should be easily
> translatable if you want to avoid the dependencies.)
If you could do the work to turn this into a plain ISO C + POSIX test case
then that would be really useful for our efforts to add a regression test.

-- 
Cheers,
Carlos