The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x c3e9826a22027a21d998d3e64882fa377b613006 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025063028-crayon-registry-8ae0@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c3e9826a22027a21d998d3e64882fa377b613006 Mon Sep 17 00:00:00 2001 From: Wentao Liang vulab@iscas.ac.cn Date: Mon, 26 May 2025 10:37:31 +0800 Subject: [PATCH] drm/amd/display: Add null pointer check for get_first_active_display()

The function mod_hdcp_hdcp1_enable_encryption() calls the function get_first_active_display(), but does not check its return value. The return value is a null pointer if the display list is empty. This will lead to a null pointer dereference in mod_hdcp_hdcp2_enable_encryption().

Add a null pointer check for get_first_active_display() and return MOD_HDCP_STATUS_DISPLAY_NOT_FOUND if the function return null.

Fixes: 2deade5ede56 ("drm/amd/display: Remove hdcp display state with mst fix") Signed-off-by: Wentao Liang vulab@iscas.ac.cn Reviewed-by: Alex Hung alex.hung@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org # v5.8

diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c index 8c137d7c032e..e58e7b93810b 100644 --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c @@ -368,6 +368,9 @@ enum mod_hdcp_status mod_hdcp_hdcp1_enable_encryption(struct mod_hdcp *hdcp) struct mod_hdcp_display *display = get_first_active_display(hdcp); enum mod_hdcp_status status = MOD_HDCP_STATUS_SUCCESS;

+ if (!display) + return MOD_HDCP_STATUS_DISPLAY_NOT_FOUND; + mutex_lock(&psp->hdcp_context.mutex); hdcp_cmd = (struct ta_hdcp_shared_memory *)psp->hdcp_context.context.mem_context.shared_buf; memset(hdcp_cmd, 0, sizeof(struct ta_hdcp_shared_memory));