[PATCH] iommu/dma: Fix leak in non-contiguous API

* [PATCH] iommu/dma: Fix leak in non-contiguous API
@ 2021-07-23  1:05 Ezequiel Garcia
  2021-07-23  5:09 ` Christoph Hellwig
  2021-07-26 12:27 ` Joerg Roedel
  0 siblings, 2 replies; 3+ messages in thread
From: Ezequiel Garcia @ 2021-07-23  1:05 UTC (permalink / raw)
  To: iommu, linux-media
  Cc: Will Deacon, stable, Ricardo Ribalda, kernel, Ezequiel Garcia,
	Christoph Hellwig

Currently, iommu_dma_alloc_noncontiguous() allocates a
struct dma_sgt_handle object to hold some state needed for
iommu_dma_free_noncontiguous().

However, the handle is neither freed nor returned explicitly by
the ->alloc_noncontiguous method, and therefore seems leaked.
This was found by code inspection, so please review carefully and test.

As a side note, it appears the struct dma_sgt_handle type is exposed
to users of the DMA-API by linux/dma-map-ops.h, but is has no users
or functions returning the type explicitly.

This may indicate it's a good idea to move the struct dma_sgt_handle type
to drivers/iommu/dma-iommu.c. The decision is left to maintainers :-)

Cc: stable@vger.kernel.org
Fixes: e817ee5f2f95c ("dma-iommu: implement ->alloc_noncontiguous")
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
---
 drivers/iommu/dma-iommu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4e34e8b26579..16c06a1aab80 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -768,6 +768,7 @@ static void iommu_dma_free_noncontiguous(struct device *dev, size_t size,
 	__iommu_dma_unmap(dev, sgt->sgl->dma_address, size);
 	__iommu_dma_free_pages(sh->pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
 	sg_free_table(&sh->sgt);
+	kfree(sh);
 }
 #endif /* CONFIG_DMA_REMAP */
 
-- 
2.32.0

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