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Commit 15727ed0 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/fbdev: Check for existence of ifbdev->vma before operations 

Commit fabef825 ("drm/i915: Drop struct_mutex around frontbuffer
flushes") adds a dependency to ifbdev->vma when flushing the framebufer,
but the checks are only against the existence of the ifbdev->fb and not
against ifbdev->vma. This leaves a window of opportunity where we may
try to operate on the fbdev prior to it being probed (thanks to
asynchronous booting).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101534


Fixes: fabef825 ("drm/i915: Drop struct_mutex around frontbuffer flushes")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170622160211.783-1-chris@chris-wilson.co.uk


Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: stable@vger.kernel.org
parent fad20834

drivers/gpu/drm/i915/intel_fbdev.c

+6 −5
Original line number Diff line number Diff line
@@ -535,13 +535,14 @@ static void intel_fbdev_destroy(struct intel_fbdev *ifbdev) 


	drm_fb_helper_fini(&ifbdev->helper);



	if (ifbdev->fb) {

	if (ifbdev->vma) {

		mutex_lock(&ifbdev->helper.dev->struct_mutex);

		intel_unpin_fb_vma(ifbdev->vma);

		mutex_unlock(&ifbdev->helper.dev->struct_mutex);

	}



	if (ifbdev->fb)

		drm_framebuffer_remove(&ifbdev->fb->base);

	}



	kfree(ifbdev);

}
@@ -765,7 +766,7 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous 
	struct intel_fbdev *ifbdev = dev_priv->fbdev;

	struct fb_info *info;



	if (!ifbdev || !ifbdev->fb)

	if (!ifbdev || !ifbdev->vma)

		return;



	info = ifbdev->helper.fbdev;
@@ -812,7 +813,7 @@ void intel_fbdev_output_poll_changed(struct drm_device *dev) 
{

	struct intel_fbdev *ifbdev = to_i915(dev)->fbdev;



	if (ifbdev && ifbdev->fb)

	if (ifbdev && ifbdev->vma)

		drm_fb_helper_hotplug_event(&ifbdev->helper);

}
@@ -824,7 +825,7 @@ void intel_fbdev_restore_mode(struct drm_device *dev) 
		return;



	intel_fbdev_sync(ifbdev);

	if (!ifbdev->fb)

	if (!ifbdev->vma)

		return;



	if (drm_fb_helper_restore_fbdev_mode_unlocked(&ifbdev->helper) == 0)