refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx> Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: David Windsor <dwindsor@xxxxxxxxx> --- drivers/media/v4l2-core/videobuf2-dma-contig.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index fb6a177..d29a07f 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -12,6 +12,7 @@ #include <linux/dma-buf.h> #include <linux/module.h> +#include <linux/refcount.h> #include <linux/scatterlist.h> #include <linux/sched.h> #include <linux/slab.h> @@ -34,7 +35,7 @@ struct vb2_dc_buf { /* MMAP related */ struct vb2_vmarea_handler handler; - atomic_t refcount; + refcount_t refcount; struct sg_table *sgt_base; /* DMABUF related */ @@ -86,7 +87,7 @@ static unsigned int vb2_dc_num_users(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; - return atomic_read(&buf->refcount); + return refcount_read(&buf->refcount); } static void vb2_dc_prepare(void *buf_priv) @@ -122,7 +123,7 @@ static void vb2_dc_put(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; - if (!atomic_dec_and_test(&buf->refcount)) + if (!refcount_dec_and_test(&buf->refcount)) return; if (buf->sgt_base) { @@ -170,7 +171,7 @@ static void *vb2_dc_alloc(struct device *dev, unsigned long attrs, buf->handler.put = vb2_dc_put; buf->handler.arg = buf; - atomic_inc(&buf->refcount); + refcount_set(&buf->refcount, 1); return buf; } @@ -407,7 +408,7 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags) return NULL; /* dmabuf keeps reference to vb2 buffer */ - atomic_inc(&buf->refcount); + refcount_inc(&buf->refcount); return dbuf; } -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html