[PATCH 1/6] drm/fb-helper: Avoid NULL ptr dereference in fb_set_suspend()

[Noralf Trønnes]

drm_fb_helper_resume_worker() uses fb_helper->fbdev to call
fb_set_suspend() which dereferences the pointer.
Move sync-canceling of the resume worker in drm_fb_helper_fini() before
setting fb_helper->fbdev to NULL.

Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
---
 drivers/gpu/drm/drm_fb_helper.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 1b8f013..2e33467 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -910,6 +910,8 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
 	if (!drm_fbdev_emulation || !fb_helper)
 		return;
 
+	cancel_work_sync(&fb_helper->resume_work);
+
 	info = fb_helper->fbdev;
 	if (info) {
 		if (info->cmap.len)
@@ -918,7 +920,6 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
 	}
 	fb_helper->fbdev = NULL;
 
-	cancel_work_sync(&fb_helper->resume_work);
 	cancel_work_sync(&fb_helper->dirty_work);
 
 	mutex_lock(&kernel_fb_helper_lock);
-- 
2.7.4