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drm/fb: Fix pointer dereference before null check.

PATCH Applied David Lechner 2 participants 2 messages Aug 2, 2017 – Aug 3, 2017

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DRM drivers DRM misc
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David Lechner

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#0 lore raw

PATCH 1/1 drm/fb: Fix pointer dereference before null check.

fb_crtc is used before a null check, so move the use after the null check.

This was just identified by inspection. I haven't actually observed a crash here, so it is possible that the null check could be unnecessary.

Signed-off-by David Lechner <[email protected]>
---
 drivers/gpu/drm/drm_fb_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/gpu/drm/drm_fb_helper.c +1 -1
index 2cc28f0..2d3f93e 100644
@@ -2424,9 +2424,9 @@ static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
 		struct drm_display_mode *mode = modes[i];
 		struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
 		struct drm_fb_offset *offset = &offsets[i];
-		struct drm_mode_set *modeset = &fb_crtc->mode_set;
 
 		if (mode && fb_crtc) {
+			struct drm_mode_set *modeset = &fb_crtc->mode_set;
 			struct drm_connector *connector =
 				fb_helper->connector_info[i]->connector;
Signature · 1 line
2.7.4
Applied
#1 lore raw
Quoted 6 lines · David Lechner

fb_crtc is used before a null check, so move the use after the null check.

This was just identified by inspection. I haven't actually observed a crash here, so it is possible that the null check could be unnecessary.

Signed-off-by David Lechner <[email protected]>

Thanks, applied.
-Daniel

Quoted 26 lines
---
 drivers/gpu/drm/drm_fb_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/gpu/drm/drm_fb_helper.c +1 -1
index 2cc28f0..2d3f93e 100644
@@ -2424,9 +2424,9 @@ static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
 		struct drm_display_mode *mode = modes[i];
 		struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
 		struct drm_fb_offset *offset = &offsets[i];
-		struct drm_mode_set *modeset = &fb_crtc->mode_set;
 
 		if (mode && fb_crtc) {
+			struct drm_mode_set *modeset = &fb_crtc->mode_set;
 			struct drm_connector *connector =
 				fb_helper->connector_info[i]->connector;
Signature · 6 lines
2.7.4

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Signature · 3 lines
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch