Hi Benjamin,
On 01/09/2023 14:44, Benjamin Gaignard wrote:
> Add 'max_allowed_buffers' field in vb2_queue struct to let drivers decide
> how many buffers could be stored in a queue.
> This request 'bufs' array to be allocated at queue init time and freed
> when releasing the queue.
> By default VB2_MAX_FRAME remains the limit.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> ---
> .../media/common/videobuf2/videobuf2-core.c | 25 +++++++++++++------
> include/media/videobuf2-core.h | 4 ++-
> 2 files changed, 20 insertions(+), 9 deletions(-)
>
This patch breaks v4l2-compliance. I see lots of issues when running the
test-media script in v4l-utils, contrib/test, among them memory leaks
and use-after-free.
I actually tested using virtme with the build scripts, but that in turn
calls the test-media script in a qemu environment, and it is at the moment
a bit tricky to set up, unless you run a debian 12 distro.
I will email the test logs directly to you since they are a bit large (>5000 lines).
Regards,
Hans
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 15b583ce0c69..dc7f6b59d237 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -411,7 +411,7 @@ static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb)
> */
> static bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, unsigned int index)
> {
> - if (index < VB2_MAX_FRAME && !q->bufs[index]) {
> + if (index < q->max_allowed_buffers && !q->bufs[index]) {
> q->bufs[index] = vb;
> vb->index = index;
> vb->vb2_queue = q;
> @@ -428,7 +428,7 @@ static bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, uns
> */
> static void vb2_queue_remove_buffer(struct vb2_queue *q, struct vb2_buffer *vb)
> {
> - if (vb->index < VB2_MAX_FRAME) {
> + if (vb->index < q->max_allowed_buffers) {
> q->bufs[vb->index] = NULL;
> vb->vb2_queue = NULL;
> }
> @@ -449,9 +449,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
> struct vb2_buffer *vb;
> int ret;
>
> - /* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */
> + /* Ensure that q->num_buffers+num_buffers is below q->max_allowed_buffers */
> num_buffers = min_t(unsigned int, num_buffers,
> - VB2_MAX_FRAME - q->num_buffers);
> + q->max_allowed_buffers - q->num_buffers);
>
> for (buffer = 0; buffer < num_buffers; ++buffer) {
> /* Allocate vb2 buffer structures */
> @@ -862,9 +862,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> /*
> * Make sure the requested values and current defaults are sane.
> */
> - WARN_ON(q->min_buffers_needed > VB2_MAX_FRAME);
> + WARN_ON(q->min_buffers_needed > q->max_allowed_buffers);
> num_buffers = max_t(unsigned int, *count, q->min_buffers_needed);
> - num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
> + num_buffers = min_t(unsigned int, num_buffers, q->max_allowed_buffers);
> memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
> /*
> * Set this now to ensure that drivers see the correct q->memory value
> @@ -980,7 +980,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> bool no_previous_buffers = !q->num_buffers;
> int ret;
>
> - if (q->num_buffers == VB2_MAX_FRAME) {
> + if (q->num_buffers == q->max_allowed_buffers) {
> dprintk(q, 1, "maximum number of buffers already allocated\n");
> return -ENOBUFS;
> }
> @@ -1009,7 +1009,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> return -EINVAL;
> }
>
> - num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
> + num_buffers = min(*count, q->max_allowed_buffers - q->num_buffers);
>
> if (requested_planes && requested_sizes) {
> num_planes = requested_planes;
> @@ -2519,6 +2519,14 @@ int vb2_core_queue_init(struct vb2_queue *q)
>
> q->memory = VB2_MEMORY_UNKNOWN;
>
> + if (!q->max_allowed_buffers)
> + q->max_allowed_buffers = VB2_MAX_FRAME;
> +
> + /* The maximum is limited by offset cookie encoding pattern */
> + q->max_allowed_buffers = min_t(unsigned int, q->max_allowed_buffers, BUFFER_INDEX_MASK);
> +
> + q->bufs = kcalloc(q->max_allowed_buffers, sizeof(*q->bufs), GFP_KERNEL);
> +
> if (q->buf_struct_size == 0)
> q->buf_struct_size = sizeof(struct vb2_buffer);
>
> @@ -2543,6 +2551,7 @@ void vb2_core_queue_release(struct vb2_queue *q)
> __vb2_queue_cancel(q);
> mutex_lock(&q->mmap_lock);
> __vb2_queue_free(q, q->num_buffers);
> + kfree(q->bufs);
> mutex_unlock(&q->mmap_lock);
> }
> EXPORT_SYMBOL_GPL(vb2_core_queue_release);
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index cd3ff1cd759d..97153c69583f 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -558,6 +558,7 @@ struct vb2_buf_ops {
> * @dma_dir: DMA mapping direction.
> * @bufs: videobuf2 buffer structures
> * @num_buffers: number of allocated/used buffers
> + * @max_allowed_buffers: upper limit of number of allocated/used buffers
> * @queued_list: list of buffers currently queued from userspace
> * @queued_count: number of buffers queued and ready for streaming.
> * @owned_by_drv_count: number of buffers owned by the driver
> @@ -619,8 +620,9 @@ struct vb2_queue {
> struct mutex mmap_lock;
> unsigned int memory;
> enum dma_data_direction dma_dir;
> - struct vb2_buffer *bufs[VB2_MAX_FRAME];
> + struct vb2_buffer **bufs;
> unsigned int num_buffers;
> + unsigned int max_allowed_buffers;
>
> struct list_head queued_list;
> unsigned int queued_count;
