[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 16/29] drivers, media: convert vb2_vmalloc_buf.refcount from atomic_t to refcount_t
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-vmalloc.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c index 3f77814..f83253a 100644 --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c @@ -13,6 +13,7 @@ #include <linux/io.h> #include <linux/module.h> #include <linux/mm.h> +#include <linux/refcount.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/vmalloc.h> @@ -26,7 +27,7 @@ struct vb2_vmalloc_buf { struct frame_vector *vec; enum dma_data_direction dma_dir; unsigned long size; - atomic_t refcount; + refcount_t refcount; struct vb2_vmarea_handler handler; struct dma_buf *dbuf; }; @@ -56,7 +57,7 @@ static void *vb2_vmalloc_alloc(struct device *dev, unsigned long attrs, return ERR_PTR(-ENOMEM); } - atomic_inc(&buf->refcount); + refcount_set(&buf->refcount, 1); return buf; } @@ -64,7 +65,7 @@ static void vb2_vmalloc_put(void *buf_priv) { struct vb2_vmalloc_buf *buf = buf_priv; - if (atomic_dec_and_test(&buf->refcount)) { + if (refcount_dec_and_test(&buf->refcount)) { vfree(buf->vaddr); kfree(buf); } @@ -161,7 +162,7 @@ static void *vb2_vmalloc_vaddr(void *buf_priv) static unsigned int vb2_vmalloc_num_users(void *buf_priv) { struct vb2_vmalloc_buf *buf = buf_priv; - return atomic_read(&buf->refcount); + return refcount_read(&buf->refcount); } static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma) @@ -368,7 +369,7 @@ static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flag return NULL; /* dmabuf keeps reference to vb2 buffer */ - atomic_inc(&buf->refcount); + refcount_inc(&buf->refcount); return dbuf; } -- 2.7.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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