linux-kernel - [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

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Date:	Mon, 16 Jun 2014 14:40:43 +0900
From:	Joonsoo Kim <iamjoonsoo.kim@....com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Michal Nazarewicz <mina86@...a86.com>
Cc:	Minchan Kim <minchan@...nel.org>,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Gleb Natapov <gleb@...nel.org>, Alexander Graf <agraf@...e.de>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	kvm@...r.kernel.org, kvm-ppc@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org,
	Zhang Yanfei <zhangyanfei@...fujitsu.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak

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.

Acked-by: Zhang Yanfei <zhangyanfei@...fujitsu.com>
Reviewed-by: Michal Nazarewicz <mina86@...a86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>

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

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