From 7d1de851632d013023cd7c89eb8664f62e5beb2c Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Wed, 12 Aug 2015 17:00:30 +0200
Subject: [PATCH] drm/irq: Check for valid VBLANK before dereference
When accessing the array of per-CRTC VBLANK structures we must always
check that the index into the array is valid before dereferencing to
avoid crashing.
Signed-off-by: Thierry Reding <treding@nvidia.com>
[danvet: Squash in my own whitespace ocd fixup in drm_vblank_count.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/drm_irq.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 120a16fe15c20..f7c8b758059f9 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -877,6 +877,7 @@ u32 drm_vblank_count(struct drm_device *dev, int crtc)
if (WARN_ON(crtc >= dev->num_crtcs))
return 0;
+
return vblank->count;
}
EXPORT_SYMBOL(drm_vblank_count);
@@ -1110,10 +1111,10 @@ void drm_vblank_put(struct drm_device *dev, int crtc)
{
struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
- if (WARN_ON(atomic_read(&vblank->refcount) == 0))
+ if (WARN_ON(crtc >= dev->num_crtcs))
return;
- if (WARN_ON(crtc >= dev->num_crtcs))
+ if (WARN_ON(atomic_read(&vblank->refcount) == 0))
return;
/* Last user schedules interrupt disable */
@@ -1158,6 +1159,9 @@ void drm_wait_one_vblank(struct drm_device *dev, int crtc)
int ret;
u32 last;
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return;
+
ret = drm_vblank_get(dev, crtc);
if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", crtc, ret))
return;
@@ -1428,6 +1432,9 @@ void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
if (!dev->num_crtcs)
return;
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return;
+
if (vblank->inmodeset) {
spin_lock_irqsave(&dev->vbl_lock, irqflags);
dev->vblank_disable_allowed = true;
--
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