SDL: kmsdrm: Add missing KMSDRM_FBFromBO() failure check

SDL Commits
1 
From 1674a04b018a86ad05088e343d74dd57d7f7c9ec Mon Sep 17 00:00:00 2001
From: Cameron Gutman <[EMAIL REDACTED]>
Date: Thu, 2 Apr 2026 22:02:18 -0500
Subject: [PATCH] kmsdrm: Add missing KMSDRM_FBFromBO() failure check

---
 src/video/kmsdrm/SDL_kmsdrmmouse.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/video/kmsdrm/SDL_kmsdrmmouse.c b/src/video/kmsdrm/SDL_kmsdrmmouse.c
index 8f48df3e8ee2c..1cee269dd65f2 100644
--- a/src/video/kmsdrm/SDL_kmsdrmmouse.c
+++ b/src/video/kmsdrm/SDL_kmsdrmmouse.c
@@ -215,6 +215,11 @@ static bool KMSDRM_DumpCursorToBO(SDL_VideoDisplay *display, SDL_Mouse *mouse, S
         KMSDRM_FBInfo *fb = KMSDRM_FBFromBO(video_device, dispdata->cursor_bo);
         KMSDRM_PlaneInfo info;
 
+        if (!fb) {
+            result = SDL_SetError("Failed to get cursor FB from BO");
+            goto cleanup;
+        }
+
         // Show the GBM BO buffer on the cursor plane.
         SDL_zero(info);
         info.plane = dispdata->cursor_plane;