From: Emil Velikov Date: Thu, 25 Aug 2011 20:36:51 +0000 (+0100) Subject: drm/nv04/crtc: Bail out if FB is not bound to crtc X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0e83bb4eee1c504ab98367b4f7d1bc337ab213d2;p=linux-beck.git drm/nv04/crtc: Bail out if FB is not bound to crtc This commit resolves a possible 'NULL pointer dereference' It uses the same approach as radeon, intel and nouveau/nv50 Fixes bug 'Nouveau: Kernel oops when unplugging external monitor' https://bugs.freedesktop.org/show_bug.cgi?id=40336 Signed-off-by: Emil Velikov Signed-off-by: Ben Skeggs --- diff --git a/drivers/gpu/drm/nouveau/nv04_crtc.c b/drivers/gpu/drm/nouveau/nv04_crtc.c index 118261d4927a..5e45398a9e2d 100644 --- a/drivers/gpu/drm/nouveau/nv04_crtc.c +++ b/drivers/gpu/drm/nouveau/nv04_crtc.c @@ -781,11 +781,20 @@ nv04_crtc_do_mode_set_base(struct drm_crtc *crtc, struct drm_device *dev = crtc->dev; struct drm_nouveau_private *dev_priv = dev->dev_private; struct nv04_crtc_reg *regp = &dev_priv->mode_reg.crtc_reg[nv_crtc->index]; - struct drm_framebuffer *drm_fb = nv_crtc->base.fb; - struct nouveau_framebuffer *fb = nouveau_framebuffer(drm_fb); + struct drm_framebuffer *drm_fb; + struct nouveau_framebuffer *fb; int arb_burst, arb_lwm; int ret; + NV_DEBUG_KMS(dev, "index %d\n", nv_crtc->index); + + /* no fb bound */ + if (!atomic && !crtc->fb) { + NV_DEBUG_KMS(dev, "No FB bound\n"); + return 0; + } + + /* If atomic, we want to switch to the fb we were passed, so * now we update pointers to do that. (We don't pin; just * assume we're already pinned and update the base address.) @@ -794,6 +803,8 @@ nv04_crtc_do_mode_set_base(struct drm_crtc *crtc, drm_fb = passed_fb; fb = nouveau_framebuffer(passed_fb); } else { + drm_fb = crtc->fb; + fb = nouveau_framebuffer(crtc->fb); /* If not atomic, we can go ahead and pin, and unpin the * old fb we were passed. */