From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 9E3856B0092 for ; Wed, 19 Jan 2011 19:02:08 -0500 (EST) Date: Thu, 20 Jan 2011 01:01:47 +0100 From: Andrea Arcangeli Subject: Re: 2.6.38-rc1 problems with khugepaged Message-ID: <20110120000147.GR9506@random.random> References: <20110119155954.GA2272@kryptos.osrc.amd.com> <20110119214523.GF2232@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110119214523.GF2232@cmpxchg.org> Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: werner , Borislav Petkov , Ilya Dryomov , linux-mm , linux-kernel@vger.kernel.org List-ID: On Wed, Jan 19, 2011 at 10:45:23PM +0100, Johannes Weiner wrote: > Hi, > > On Wed, Jan 19, 2011 at 04:59:54PM +0100, Borislav Petkov wrote: > > Adding some more parties to CC. > > > > On Wed, Jan 19, 2011 at 09:45:25AM -0400, werner wrote: > > > ** Help Help Help *** > > > > > > My computer crashs on booting ... :( :( > > That sucks! > > I cross-compiled for 32-bit and was able to match up the disassembly > against the code line from your oops report. Apparently the pte was > an invalid pointer, and it makes perfect sense: we unmap the highpte > _before_ we access the pointer again for __collapse_huge_page_copy(). > > Can you test with this fix applied? It is only compile-tested, I too > have no 32-bit installations anymore. Thanks Johannes, I already sent the same fix a few minutes ago, it is also confirmed to work from Ilya in Message-ID: <20110119224950.GA3429@kwango.lan.net> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 1be1034..e187454 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1839,9 +1839,9 @@ static void collapse_huge_page(struct mm_struct *mm, > spin_lock(ptl); > isolated = __collapse_huge_page_isolate(vma, address, pte); > spin_unlock(ptl); > - pte_unmap(pte); > > if (unlikely(!isolated)) { > + pte_unmap(pte); > spin_lock(&mm->page_table_lock); > BUG_ON(!pmd_none(*pmd)); > set_pmd_at(mm, address, pmd, _pmd); > @@ -1858,6 +1858,7 @@ static void collapse_huge_page(struct mm_struct *mm, > anon_vma_unlock(vma->anon_vma); > > __collapse_huge_page_copy(pte, new_page, vma, address, ptl); > + pte_unmap(pte); > __SetPageUptodate(new_page); > pgtable = pmd_pgtable(_pmd); > VM_BUG_ON(page_count(pgtable) != 1); Good thing your fix is identical to mine ;). -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org