Re: [RFC PATCH v4 1/5] glibc: Perform rseq(2) registration at nptl init and thread creation

Florian Weimer
2018-11-23T17:39:21Z

* Rich Felker:

> On Fri, Nov 23, 2018 at 12:05:20PM -0500, Mathieu Desnoyers wrote:
>> There has been presumptions about signals being blocked when the thread
>> exits throughout this email thread. Out of curiosity, what code is
>> responsible for disabling signals in this situation ? Related to this,
>> is it valid to access a IE model TLS variable from a signal handler at
>> _any_ point where the signal handler nests over thread's execution ?
>> This includes early start and just before invoking the exit system call.
>
> It should be valid to access *any* TLS object like this, but the
> standards don't cover it well.

C++ makes it undefined:

<http://eel.is/c++draft/support.signal#def:evaluation,signal-safe>

Thanks,
Florian