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authorDavid Rientjes <rientjes@google.com>2011-05-24 17:12:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-25 08:39:29 -0700
commita197b59ae6e8bee56fcef37ea2482dc08414e2ac (patch)
treeead0890373cc9c36321364efbad73a25898076ab
parentba93fa81b5f2bf0076407a3a777fff122ce16220 (diff)
downloadop-kernel-dev-a197b59ae6e8bee56fcef37ea2482dc08414e2ac.zip
op-kernel-dev-a197b59ae6e8bee56fcef37ea2482dc08414e2ac.tar.gz
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>
-rw-r--r--mm/page_alloc.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 01e6b61..10a8c6d 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
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