linux-kernel - [PATCH] drm/msm: return early when allocating fbdev fails

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Date:   Wed, 22 Feb 2023 10:56:49 -0500
From:   Tom Rix <trix@...hat.com>
To:     robdclark@...il.com, quic_abhinavk@...cinc.com,
        dmitry.baryshkov@...aro.org, sean@...rly.run, airlied@...il.com,
        daniel@...ll.ch, nathan@...nel.org, ndesaulniers@...gle.com,
        tzimmermann@...e.de, javierm@...hat.com
Cc:     linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, Tom Rix <trix@...hat.com>
Subject: [PATCH] drm/msm: return early when allocating fbdev fails

building with clang and W=1 reports
drivers/gpu/drm/msm/msm_fbdev.c:144:6: error: variable 'helper' is used
  uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
  if (!fbdev)
      ^~~~~~

helper is only initialized after fbdev succeeds, so is in a garbage state at
the fail: label.  There is nothing to unwinded if fbdev alloaction fails,
return NULL.

Fixes: 3fb1f62f80a1 ("drm/fb-helper: Remove drm_fb_helper_unprepare() from drm_fb_helper_fini()")
Signed-off-by: Tom Rix <trix@...hat.com>
---
 drivers/gpu/drm/msm/msm_fbdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index c804e5ba682a..c1356aff87da 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -142,7 +142,7 @@ struct drm_fb_helper *msm_fbdev_init(struct drm_device *dev)
 
 	fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
 	if (!fbdev)
-		goto fail;
+		return NULL;
 
 	helper = &fbdev->base;
 
-- 
2.27.0