From 10e59fbdef13597836bd6459095caa02c80af3d7 Mon Sep 17 00:00:00 2001 From: Haotian Zhang Date: Tue, 1 Sep 2026 10:23:09 +0800 Subject: [PATCH] media: v4l2-h264: Fix memcmp() size in B1 reference list comparison In v4l2_h264_build_b_ref_lists(), the B0/B1 list equality check passes the entry count builder->num_valid to memcmp() instead of a byte size. Since struct v4l2_h264_reference is two bytes (fields and index), only half of each list is compared, so distinct lists can be wrongly treated as equal and trigger an incorrect swap(b1_reflist[0], b1_reflist[1]). Change the memcmp() size argument to sizeof(b1_reflist[0]) * builder->num_valid so that the full byte length of both reference lists is compared. Fixes: 624922a2739b ("media: v4l2-core: Add helpers to build the H264 P/B0/B1 reflists") Suggested-by: Nicolas Dufresne Cc: stable@vger.kernel.org Signed-off-by: Haotian Zhang Reviewed-by: Nicolas Dufresne Signed-off-by: Hans Verkuil --- drivers/media/v4l2-core/v4l2-h264.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-core/v4l2-h264.c index c00197d095e7..2323f559c6a3 100644 --- a/drivers/media/v4l2-core/v4l2-h264.c +++ b/drivers/media/v4l2-core/v4l2-h264.c @@ -440,7 +440,8 @@ v4l2_h264_build_b_ref_lists(const struct v4l2_h264_reflist_builder *builder, } if (builder->num_valid > 1 && - !memcmp(b1_reflist, b0_reflist, builder->num_valid)) + !memcmp(b1_reflist, b0_reflist, + sizeof(b1_reflist[0]) * builder->num_valid)) swap(b1_reflist[0], b1_reflist[1]); print_ref_list_b(builder, b0_reflist, 0);