From a197b59ae6e8bee56fcef37ea2482dc08414e2ac Mon Sep 17 00:00:00 2001 From: David Rientjes <rientjes@google.com> Date: Tue, 24 May 2011 17:12:35 -0700 Subject: [PATCH] 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> --- mm/page_alloc.c | 4 ++++ 1 file changed, 4 insertions(+) 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 -- GitLab