* [PATCH 3.15 122/122] mm/numa: Remove BUG_ON() in __handle_mm_fault()
[not found] <20140707235734.234226883@linuxfoundation.org>
@ 2014-07-07 23:58 ` Greg Kroah-Hartman
0 siblings, 0 replies; only message in thread
From: Greg Kroah-Hartman @ 2014-07-07 23:58 UTC (permalink / raw)
To: linux-kernel
Cc: Greg Kroah-Hartman, stable, Rik van Riel, Naoya Horiguchi,
Sunil Pandey, Peter Zijlstra, Andrew Morton, Johannes Weiner,
Kirill A. Shutemov, Linus Torvalds, Mel Gorman, linux-mm,
lwoodman, dave.hansen, Ingo Molnar
3.15-stable review patch. If anyone has any objections, please let me know.
------------------
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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