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authorMarek Szyprowski <m.szyprowski@samsung.com>2012-06-12 10:18:16 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-11-25 17:21:32 -0200
commitd81e870d5afa1b0a95ea94c4052d3c7e973fae8c (patch)
treefbf9102a76c986ca9b6527570d160c905e3f9e7c /drivers/media
parent67a5d0cebf30020bdc4846892adf360c57610268 (diff)
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[media] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned
The DMA transfer must be aligned to a specific value. If userptr is not aligned to DMA requirements then unexpected corruptions of the memory may occur before or after a buffer. To prevent such situations, all unligned userptr buffers are rejected at VIDIOC_QBUF. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/v4l2-core/videobuf2-dma-contig.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index b35f38e9f2d7..27de1bb731db 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -491,6 +491,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
struct vm_area_struct *vma;
struct sg_table *sgt;
unsigned long contig_size;
+ unsigned long dma_align = dma_get_cache_alignment();
+
+ /* Only cache aligned DMA transfers are reliable */
+ if (!IS_ALIGNED(vaddr | size, dma_align)) {
+ pr_debug("user data must be aligned to %lu bytes\n", dma_align);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (!size) {
+ pr_debug("size is zero\n");
+ return ERR_PTR(-EINVAL);
+ }
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)