[PATCH 1/4] dmapool: Fix overflow condition in pool_find_page
From: robin.murphy@arm.com (Robin Murphy)
Date: 2015-09-25 12:16:00
Also in:
linux-arch, linux-mm, lkml
Subsystem:
memory management, memory management - misc, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
If a DMA pool lies at the very top of the dma_addr_t range (as may happen with an IOMMU involved), the calculated end address of the pool wraps around to zero, and page lookup always fails. Tweak the relevant calculation to be overflow-proof. Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- mm/dmapool.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/dmapool.c b/mm/dmapool.c
index 71a8998..312a716 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c@@ -394,7 +394,7 @@ static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) list_for_each_entry(page, &pool->page_list, page_list) { if (dma < page->dma) continue; - if (dma < (page->dma + pool->allocation)) + if ((dma - page->dma) < pool->allocation) return page; } return NULL;
--
1.9.1