From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 14 Aug 2007 16:45:34 +1000 From: David Gibson To: gregkh@suse.de Subject: Re: patch powerpc-fix-size-check-for-hugetlbfs.patch queued to -stable tree Message-ID: <20070814064534.GE8791@localhost.localdomain> References: <1186551855.938.164.camel@localhost.localdomain> <20070813234218.4796D14540D0@imap.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20070813234218.4796D14540D0@imap.suse.de> Cc: stable-commits@vger.kernel.org, paulus@samba.org, linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Aug 13, 2007 at 04:26:27PM -0700, gregkh@suse.de wrote: > > This is a note to let you know that we have just queued up the patch titled > > Subject: powerpc: Fix size check for hugetlbfs > > to the 2.6.22-stable tree. Its filename is > > powerpc-fix-size-check-for-hugetlbfs.patch > > A git repo of this tree can be found at > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > > >From benh@kernel.crashing.org Mon Aug 13 16:17:09 2007 > From: Benjamin Herrenschmidt > Date: Wed, 08 Aug 2007 15:44:15 +1000 > Subject: powerpc: Fix size check for hugetlbfs > To: linuxppc-dev list > Cc: Paul Mackerras , stable@kernel.org > Message-ID: <1186551855.938.164.camel@localhost.localdomain> > > From: Benjamin Herrenschmidt > > My "slices" address space management code that was added in 2.6.22 > implementation of get_unmapped_area() doesn't properly check that the > size is a multiple of the requested page size. This allows userland to > create VMAs that aren't a multiple of the huge page size with hugetlbfs > (since hugetlbfs entirely relies on get_unmapped_area() to do that > checking) which leads to a kernel BUG() when such areas are torn down. Ok, I said I was going to look into a libhugetlbfs testcase for this. Doesn't appear there's specifically a testcase for misaligned size - I'll add one. However, it seems the current kernel, on ppc64, gives a testcase failure on 'misaligned_offset', because it's not failing a mapping with a non-hugepage aligned file offset. I'm not sure (yet) if this failure is also caused by the new slice code, but it seems a likely candidate. Still investigating... -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson