5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Haotian Zhang commit 10e59fbdef13597836bd6459095caa02c80af3d7 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- drivers/media/v4l2-core/v4l2-h264.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/media/v4l2-core/v4l2-h264.c +++ b/drivers/media/v4l2-core/v4l2-h264.c @@ -258,7 +258,8 @@ v4l2_h264_build_b_ref_lists(const struct v4l2_h264_b1_ref_list_cmp, NULL, 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]); } EXPORT_SYMBOL_GPL(v4l2_h264_build_b_ref_lists);