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authorRik van Riel <riel@redhat.com>2014-04-29 15:36:15 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-09 11:21:32 -0700
commit3bb0aa773f1918e0da5346e12aec05aaacbf2441 (patch)
parent3adcfcd40cffe6b8e66aebb373c3fbaf763e04b3 (diff)
mm/numa: Remove BUG_ON() in __handle_mm_fault()
commit 107437febd495a50e2cd09c81bbaa84d30e57b07 upstream. Changing PTEs and PMDs to pte_numa & pmd_numa is done with the mmap_sem held for reading, which means a pmd can be instantiated and turned into a numa one while __handle_mm_fault() is examining the value of old_pmd. If that happens, __handle_mm_fault() should just return and let the page fault retry, instead of throwing an oops. This is handled by the test for pmd_trans_huge(*pmd) below. Signed-off-by: Rik van Riel <riel@redhat.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Sunil Pandey <sunil.k.pandey@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: linux-mm@kvack.org Cc: lwoodman@redhat.com Cc: dave.hansen@intel.com Link: http://lkml.kernel.org/r/20140429153615.2d72098e@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Patrick McLean <chutzpah@gentoo.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 0 insertions, 3 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 037b812a9531..e302ae1dcce0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3920,9 +3920,6 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- /* THP should already have been handled */
- BUG_ON(pmd_numa(*pmd));
* Use __pte_alloc instead of pte_alloc_map, because we can't
* run pte_offset_map on the pmd, if an huge pmd could