linux-kernel - Process-shared futexes on hugepages puts the kernel in an infinite loop in 2.6.32.11; is this fixed now?

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Date:	Fri, 16 Apr 2010 23:45:22 +0800
From:	r6144 <rainy6144@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Process-shared futexes on hugepages puts the kernel in an infinite
 loop in 2.6.32.11; is this fixed now?

Hello all,

I'm having an annoying kernel bug regarding huge pages in Fedora 12:

https://bugzilla.redhat.com/show_bug.cgi?id=552257

Basically I want to use huge pages in a multithreaded number crunching
program, which happens to use process-shared semaphores (because fftw
does it).  The futex for the semaphore ends up lying on a huge page, and
I then get an endless loop in get_futex_key(), apparently because the
anonymous huge page containing the futex does not have a page->mapping.
A test case is provided in the above link.

I reported the bug to Fedora bugzilla months ago, but haven't received
any feedback yet.  The Fedora kernel is based on 2.6.32.11, and a
cursory glance at the 2.6.34-rc3 source does not yield any relevant
change.

So, could anyone tell me if the current mainline kernel might act better
in this respect, before I get around to compiling it?

Thank you very much.

Please CC me as I'm not subscribed.

r6144

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