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From: "carlos at redhat dot com" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug libc/25912] Possible race in free_check() with MALLOC_CHECK_=3
Date: Wed, 06 May 2020 15:16:04 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D25912

Carlos O'Donell <carlos at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID
                 CC|                            |carlos at redhat dot com

--- Comment #1 from Carlos O'Donell <carlos at redhat dot com> ---
(In reply to Vinitha Vijayan from comment #0)
> In case if from signal handler a new malloc request is raised, the thread
> seems to be hanging forever.

Your test is invalid.

Please see:
https://www.gnu.org/software/libc/manual/html_node/Basic-Allocation.html#Ba=
sic-Allocation

malloc() is marked AS-unsafe, which means it is not safe to call in an
asynchronous signal handler.

Likewise review 'man signal-safety', and see that 'malloc' is not in the li=
st
of signal-safe functions.

> Could you please confirm if this is a bug?

This is not a bug. The program has detected the invalid free and raised a
SIGABRT, but your handler does something invalid and you hang.

I'm marking this RESOLVED/INVALID.

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