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List:       apr-dev
Subject:    Re: testreslist failures / thread-safety issues
From:       Jeff Trawick <trawick () gmail ! com>
Date:       2011-05-24 20:34:05
Message-ID: BANLkTi=0aQsArHSrZsTam6iT_R4wVBGT+A () mail ! gmail ! com
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On Tue, May 24, 2011 at 4:01 PM, Stefan Fritsch <sf@sfritsch.de> wrote:
> On Sunday 22 May 2011, Jeff Trawick wrote:
>> > Can those people who frequently hit the testreslist failures
>> > please check if this commit helps? From a powerpc Debian build
>> > host, it looks promising, but I don't have direct access to that
>> > machine and can't do repeated tests there.
>>
>> no luck on Windows 7
>>
>> apr-util 1.3.x, gcc, still fails
>> apr trunk, Visual C++ 2008 Express, still fails
>>
>> Seven:~/svn/apr-util-1.3.x-xx/test$ ./testall -v testreslist
>> testreslist         : /Line 258: expected <10>, but saw <20>
>> FAILED 1 of 1
>> Failed Tests            Total   Fail    Failed %
>> ===================================================
>> testreslist                 1      1    100.00%
>
> Can you try the attached patch in addition? Is this failure sporadic
> or always?

tested with apr-util 1.3.x and gcc
no change
I don't remember if this test has ever worked for me in this environment

>
>
>> > Unfortunately, there are also other thread-safety issues in
>> > apr/apr- util. Using hellgrind on testreslist found these
>> > issues:
>> >
>> > - unsafe read of pool->child in apr_pool_destroy. This one
>> > worries me. If a subpool is destroyed in one thread while the
>> > pool itself is destroyed in another thread, it can happen that
>> > apr_pool_destroy is called again for the subpool. This would
>> > likely lead to a crash. Any ideas on how to fix this without
>> > sacrificing too much performance?
>> >
>> > - unsafe read of allocator->max_index (PR 48535, likely not
>> > critical)
>> >
>> > - unsafe read of _myself->thd_cnt in thread_pool_cleanup()
>> > (likely not critical; but there seem to be other thread-safety
>> > issues in that file, at least the access of thd_high is also
>> > unsafe)
>
> The last one is fixed by the attached patch. I no longer think that it
> is no problem.
>



-- 
Born in Roswell... married an alien...

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