| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.15 122/122] mm/numa: Remove BUG_ON() in __handle_mm_fault() | Date | Mon, 7 Jul 2014 16:58:04 -0700 |
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3.15-stable review patch. If anyone has any objections, please let me know.
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From: Rik van Riel <riel@redhat.com>
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>
--- mm/memory.c | 3 --- 1 file changed, 3 deletions(-)
--- a/mm/memory.c +++ b/mm/memory.c @@ -3920,9 +3920,6 @@ static int __handle_mm_fault(struct mm_s } } - /* 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
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