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| author | David Rientjes <rientjes@google.com> | 2011-05-24 17:12:35 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-25 08:39:29 -0700 |
| commit | a197b59ae6e8bee56fcef37ea2482dc08414e2ac (patch) | |
| tree | ead0890373cc9c36321364efbad73a25898076ab /mm | |
| parent | ba93fa81b5f2bf0076407a3a777fff122ce16220 (diff) | |
| download | lwn-a197b59ae6e8bee56fcef37ea2482dc08414e2ac.tar.gz lwn-a197b59ae6e8bee56fcef37ea2482dc08414e2ac.zip | |
mm: fail GFP_DMA allocations when ZONE_DMA is not configured
The page allocator will improperly return a page from ZONE_NORMAL even
when __GFP_DMA is passed if CONFIG_ZONE_DMA is disabled. The caller
expects DMA memory, perhaps for ISA devices with 16-bit address registers,
and may get higher memory resulting in undefined behavior.
This patch causes the page allocator to return NULL in such circumstances
with a warning emitted to the kernel log on the first occurrence.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 01e6b614839d..10a8c6da385f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2247,6 +2247,10 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, if (should_fail_alloc_page(gfp_mask, order)) return NULL; +#ifndef CONFIG_ZONE_DMA + if (WARN_ON_ONCE(gfp_mask & __GFP_DMA)) + return NULL; +#endif /* * Check the zones suitable for the gfp_mask contain at least one |