From 3e07f57d4ad7dcc85690de9f595a94ef9ad3fae1 Mon Sep 17 00:00:00 2001
From: Yiwei Zhang <zzyiwei@chromium.org>
Date: Sun, 26 Oct 2025 20:20:46 -0700
Subject: [PATCH] llvmpipe: fix udmabuf mmap error check

Upon failing to mmap, MAP_FAILED (void *)-1 is returned instead of NULL.

Fixes: d74ea2c117f ("llvmpipe: Implement dmabuf handling")
Reviewed-by: Christian Gmeiner <cgmeiner@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38074>
---
 src/gallium/drivers/llvmpipe/lp_texture.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/gallium/drivers/llvmpipe/lp_texture.c b/src/gallium/drivers/llvmpipe/lp_texture.c
index b0eea5a932c..593f6d4d85f 100644
--- a/src/gallium/drivers/llvmpipe/lp_texture.c
+++ b/src/gallium/drivers/llvmpipe/lp_texture.c
@@ -1415,8 +1415,7 @@ llvmpipe_resource_alloc_udmabuf(struct llvmpipe_screen *screen,
 
       struct pipe_memory_allocation *data =
          mmap(NULL, size, PROT_WRITE | PROT_READ, MAP_SHARED, mem_fd, 0);
-
-      if (!data)
+      if (data == MAP_FAILED)
          goto fail;
 
       alloc->mem_fd = mem_fd;