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Re: server crash in authz object pool

From: Branko Čibej <brane_at_apache.org>
Date: Mon, 12 Feb 2018 14:24:56 +0100

On 12.02.2018 13:07, Stefan Sperling wrote:
> On Mon, Feb 12, 2018 at 12:50:12PM +0100, Stefan Sperling wrote:
>> The svn-bb-openbsd bot has found a crash in the object pool code.
>>
>> It is triggered when running RA serf tests on OpenBSD. The httpd
>> work processes crash due to what looks like a use-after-free (0xdf
>> means this byte of memory has been freed).
>>
>> I can reproduce this on sparc64 and amd64 machines.
>> The build is without APR_HAS_THREADS, using the prefork MPM with HTTPD 2.2.
>> Let me know if you need more details. I have no time at present to hunt
>> this down myself, so I'm sending this info to the list in hope that it
>> will be useful.
> Hmm, a quick check revealed that this started happening with r1823787,
> where I stopped pre-loading libpthread.so into httpd. To the best of
> my knowledge dlopen() now works without this hack on OpenBSD.
>
> However, the httpd modules in my build *are* linked to libpthread.so
> for some reason, even though APR is compiled without threads:
>
> $ ldd modules/svn-trunk/{mod_authz_svn,mod_dav_svn,mod_dontdothat}.so | grep pthread
> 00001afb97159000 00001afb97362000 rlib 0 10 0 /usr/lib/libpthread.so.25.1
> 00001afb2c499000 00001afb2c6a2000 rlib 0 10 0 /usr/lib/libpthread.so.25.1
> 00001afb81409000 00001afb81612000 rlib 0 3 0 /usr/lib/libpthread.so.25.1
>
> So this could just be a local problem in my build.
> I'll investigate this later, and revert r1823787 for now.

Perhaps one of the other dependencies is pulling in pthreads?

Out of interest: why are you using APR without threads?

-- Brane
Received on 2018-02-12 14:25:14 CET

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