[PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak
From: minchan@kernel.org (Minchan Kim)
Date: 2014-06-16 06:26:58
Also in:
kvm, linux-mm, linuxppc-dev, lkml
Hi, Joonsoo On Mon, Jun 16, 2014 at 02:40:43PM +0900, Joonsoo Kim wrote:
We should free memory for bitmap when we find zone mis-match, otherwise this memory will leak. Additionally, I copy code comment from PPC KVM's CMA code to inform why we need to check zone mis-match. * Note Minchan suggested to add a tag for the stable, but, I don't do it, because I found this possibility during code-review and, IMO, this patch isn't suitable for stable tree.
Nice idea to put the comment in here. Thanks Joonsoo. It seems you obey "It must fix a real bug that bothers people" on Documentation/stable_kernel_rules.txt but it's a really obvious bug and hard to get a report from people because limited user and hard to detect small such small memory leak. In my experince, Andrew perfered stable marking for such a obvious problem but simple fix like this but not sure so let's pass the decision to him and will learn a lesson from him and will follow the decision from now on. Thanks. Acked-by: Minchan Kim <minchan@kernel.org>
quoted hunk ↗ jump to hunk
Acked-by: Zhang Yanfei <redacted> Reviewed-by: Michal Nazarewicz <redacted> Reviewed-by: Aneesh Kumar K.V <redacted> Signed-off-by: Joonsoo Kim <redacted>diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c index 83969f8..6467c91 100644 --- a/drivers/base/dma-contiguous.c +++ b/drivers/base/dma-contiguous.c@@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma) base_pfn = pfn; for (j = pageblock_nr_pages; j; --j, pfn++) { WARN_ON_ONCE(!pfn_valid(pfn)); + /* + * alloc_contig_range requires the pfn range + * specified to be in the same zone. Make this + * simple by forcing the entire CMA resv range + * to be in the same zone. + */ if (page_zone(pfn_to_page(pfn)) != zone) - return -EINVAL; + goto err; } init_cma_reserved_pageblock(pfn_to_page(base_pfn)); } while (--i); mutex_init(&cma->lock); return 0; + +err: + kfree(cma->bitmap); + return -EINVAL; } static struct cma cma_areas[MAX_CMA_AREAS];-- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo at kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email at kvack.org </a>
-- Kind regards, Minchan Kim