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@xxxxxxxxxxxxxx>
> 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 ;).
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