Messages in this thread | | | Date | Mon, 16 Jun 2014 15:27:19 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH v3 -next 1/9] DMA, CMA: fix possible memory leak |
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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>
> > Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> > Reviewed-by: Michal Nazarewicz <mina86@mina86.com> > Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.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 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
-- Kind regards, Minchan Kim
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