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From: Florian Weimer <fweimer@redhat.com>
To: Dominic Chen <d.c.ddcc@gmail.com>
Cc: musl@lists.openwall.com
Subject: Re: [musl] Incorrect thread TID caching
Date: Wed, 03 Feb 2021 08:16:30 +0100	[thread overview]
Message-ID: <87zh0ltycx.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <62be4b85-4a42-413e-a83f-866eab4d601a@gmail.com> (Dominic Chen's message of "Tue, 2 Feb 2021 23:04:23 -0500")

* Dominic Chen:

> From a quick skim of other libc implementations, both bionic and glibc
> don't seem to cache TID, and directly call the gettid system call
> inside raise().

Of course glibc has a TID cache.  It doesn't use it in raise (mostly to
get abort working after vfork), but it's definitely needed in other
places.

If you use the clone system call wrapper in threading (not fork/vfork)
mode, you cannot call any libc functions afterwards, including the
syscall function.  Instead, you have to issue direct system calls.

Thanks,
Florian
-- 
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Commercial register: Amtsgericht Muenchen, HRB 153243,
Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill


  reply	other threads:[~2021-02-03  7:16 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-03  4:04 Dominic Chen
2021-02-03  7:16 ` Florian Weimer [this message]
2021-02-03 19:21 ` Rich Felker
2021-02-03 20:21   ` Dominic Chen
2021-02-03 21:01     ` Rich Felker
2021-02-03 22:30       ` Dominic Chen
2021-02-03 22:55         ` Rich Felker
2021-02-15 16:56           ` Rich Felker
2021-02-17 19:49             ` Dominic Chen
2021-02-17 20:11               ` Rich Felker
2021-02-17 21:07                 ` Rich Felker
2021-03-12 21:14                   ` Dominic Chen
2021-02-04  3:28     ` Carlos O'Donell
2021-02-04  4:22       ` Dominic Chen
2021-02-04 16:15         ` Rich Felker

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