| Message ID | 521e48fc5fc8d211ed2847070120ff4032b7a383.1441363361.git.lukas@wunner.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Jul 04, 2015 at 11:50:58AM +0200, Lukas Wunner wrote: > Currently when allocating a framebuffer fails, the gem object gets > unrefed at the bottom of the call chain in __intel_framebuffer_create, > not where it gets refed, which is in intel_framebuffer_create_for_mode > (via i915_gem_alloc_object) and in intel_user_framebuffer_create > (via drm_gem_object_lookup). > > This invites mistakes: As discovered by Tvrtko Ursulin, a double unref > has sneaked into intelfb_alloc (which calls __intel_framebuffer_create). > > As suggested by Ville Syrjälä, improve code clarity by moving the unref > away from __intel_framebuffer_create to where the gem object gets refed. > > [Changelog is in preceding patch by Tvrtko Ursulin.] > > Tested-by: Pierre Moreau <pierre.morrow@free.fr> > [MBP 5,3 2009 nvidia 9400M + 9600M GT pre-retina] > Tested-by: Paul Hordiienko <pvt.gord@gmail.com> > [MBP 6,2 2010 intel ILK + nvidia GT216 pre-retina] > Tested-by: William Brown <william@blackhats.net.au> > [MBP 8,2 2011 intel SNB + amd turks pre-retina] > Tested-by: Lukas Wunner <lukas@wunner.de> > [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina] > Tested-by: Bruno Bierbaumer <bruno@bierbaumer.net> > [MBP 11,3 2013 intel HSW + nvidia GK107 retina] > > Signed-off-by: Lukas Wunner <lukas@wunner.de> > Fixes: a8bb6818270c ("drm/i915: Fix error path leak in fbdev fb > allocation") > Cc: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/i915/intel_display.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c > index 421ac15..68d051d 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -10033,20 +10033,17 @@ __intel_framebuffer_create(struct drm_device *dev, > int ret; > > intel_fb = kzalloc(sizeof(*intel_fb), GFP_KERNEL); > - if (!intel_fb) { > - drm_gem_object_unreference(&obj->base); > + if (!intel_fb) > return ERR_PTR(-ENOMEM); > - } > > ret = intel_framebuffer_init(dev, intel_fb, mode_cmd, obj); > if (ret) > goto err; > > return &intel_fb->base; > + > err: > - drm_gem_object_unreference(&obj->base); > kfree(intel_fb); > - > return ERR_PTR(ret); > } > > @@ -10086,6 +10083,7 @@ intel_framebuffer_create_for_mode(struct drm_device *dev, > struct drm_display_mode *mode, > int depth, int bpp) > { > + struct drm_framebuffer *fb; > struct drm_i915_gem_object *obj; > struct drm_mode_fb_cmd2 mode_cmd = { 0 }; > > @@ -10100,7 +10098,11 @@ intel_framebuffer_create_for_mode(struct drm_device *dev, > bpp); > mode_cmd.pixel_format = drm_mode_legacy_fb_format(bpp, depth); > > - return intel_framebuffer_create(dev, &mode_cmd, obj); > + fb = intel_framebuffer_create(dev, &mode_cmd, obj); > + if (IS_ERR(fb)) > + drm_gem_object_unreference_unlocked(&obj->base); > + > + return fb; > } > > static struct drm_framebuffer * > @@ -14289,6 +14291,7 @@ intel_user_framebuffer_create(struct drm_device *dev, > struct drm_file *filp, > struct drm_mode_fb_cmd2 *mode_cmd) > { > + struct drm_framebuffer *fb; > struct drm_i915_gem_object *obj; > > obj = to_intel_bo(drm_gem_object_lookup(dev, filp, > @@ -14296,7 +14299,11 @@ intel_user_framebuffer_create(struct drm_device *dev, > if (&obj->base == NULL) > return ERR_PTR(-ENOENT); > > - return intel_framebuffer_create(dev, mode_cmd, obj); > + fb = intel_framebuffer_create(dev, mode_cmd, obj); > + if (IS_ERR(fb)) > + drm_gem_object_unreference_unlocked(&obj->base); > + > + return fb; This one looks good to me Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > } > > #ifndef CONFIG_DRM_FBDEV_EMULATION > -- > 2.1.0
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 421ac15..68d051d 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -10033,20 +10033,17 @@ __intel_framebuffer_create(struct drm_device *dev, int ret; intel_fb = kzalloc(sizeof(*intel_fb), GFP_KERNEL); - if (!intel_fb) { - drm_gem_object_unreference(&obj->base); + if (!intel_fb) return ERR_PTR(-ENOMEM); - } ret = intel_framebuffer_init(dev, intel_fb, mode_cmd, obj); if (ret) goto err; return &intel_fb->base; + err: - drm_gem_object_unreference(&obj->base); kfree(intel_fb); - return ERR_PTR(ret); } @@ -10086,6 +10083,7 @@ intel_framebuffer_create_for_mode(struct drm_device *dev, struct drm_display_mode *mode, int depth, int bpp) { + struct drm_framebuffer *fb; struct drm_i915_gem_object *obj; struct drm_mode_fb_cmd2 mode_cmd = { 0 }; @@ -10100,7 +10098,11 @@ intel_framebuffer_create_for_mode(struct drm_device *dev, bpp); mode_cmd.pixel_format = drm_mode_legacy_fb_format(bpp, depth); - return intel_framebuffer_create(dev, &mode_cmd, obj); + fb = intel_framebuffer_create(dev, &mode_cmd, obj); + if (IS_ERR(fb)) + drm_gem_object_unreference_unlocked(&obj->base); + + return fb; } static struct drm_framebuffer * @@ -14289,6 +14291,7 @@ intel_user_framebuffer_create(struct drm_device *dev, struct drm_file *filp, struct drm_mode_fb_cmd2 *mode_cmd) { + struct drm_framebuffer *fb; struct drm_i915_gem_object *obj; obj = to_intel_bo(drm_gem_object_lookup(dev, filp, @@ -14296,7 +14299,11 @@ intel_user_framebuffer_create(struct drm_device *dev, if (&obj->base == NULL) return ERR_PTR(-ENOENT); - return intel_framebuffer_create(dev, mode_cmd, obj); + fb = intel_framebuffer_create(dev, mode_cmd, obj); + if (IS_ERR(fb)) + drm_gem_object_unreference_unlocked(&obj->base); + + return fb; } #ifndef CONFIG_DRM_FBDEV_EMULATION