On Fri, Feb 19, 2016 at 02:06:00PM +0000, Russell King - ARM Linux wrote: > On Fri, Feb 19, 2016 at 09:12:04AM +0100, Rabin Vincent wrote: > > Given a device which uses arm_coherent_dma_ops and on which > > dev_get_cma_area(dev) returns non-NULL, the following usage of the DMA > > API with gfp=0 results in a memory leak and memory corruption. > > > > p = dma_alloc_coherent(dev, sz, &dma, 0); > > if (p) > > dma_free_coherent(dev, sz, p, dma); > > > > The memory leak is because the alloc allocates using > > __alloc_simple_buffer() but the free attempts > > dma_release_from_contiguous(), which does not do free anything since the > > page is not in the CMA area. > > I'd really like to see a better solution to this problem: over the course > of the years, I've seen a number of patches that rearrange the test order > at allocation time because of some problem or the other. > > What we need is a better way to ensure that we use the correct release > functionality - having two independent set of tests where the order > matters is really not very good. I've sent a v2 of this series which refactors the code so that we no longer have two independent sets of tests. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>