After spending slightly more time than I'd care to admit debugging the various and presumably spectacular way things fail when you pass too low a value to drm_vblank_init() (thanks console-lock for not letting me see the carnage!), I decided it might be a good idea to add some sanity checking.
Signed-off-by: Rob Clark robdclark@gmail.com --- btw, I wonder if we could add a module param hack to toss initial modeset off to a workqueue to sneak it out from the tyranny of console_lock?
drivers/gpu/drm/drm_irq.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 0de123a..6f16a104 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -730,6 +730,8 @@ EXPORT_SYMBOL(drm_get_last_vbltimestamp); */ u32 drm_vblank_count(struct drm_device *dev, int crtc) { + if (WARN_ON(crtc >= dev->num_crtcs)) + return 0; return atomic_read(&dev->vblank[crtc].count); } EXPORT_SYMBOL(drm_vblank_count); @@ -752,6 +754,9 @@ u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, { u32 cur_vblank;
+ if (WARN_ON(crtc >= dev->num_crtcs)) + return 0; + /* Read timestamp from slot of _vblank_time ringbuffer * that corresponds to current vblank count. Retry if * count has incremented during readout. This works like @@ -927,6 +932,9 @@ int drm_vblank_get(struct drm_device *dev, int crtc) unsigned long irqflags; int ret = 0;
+ if (WARN_ON(crtc >= dev->num_crtcs)) + return -EINVAL; + spin_lock_irqsave(&dev->vbl_lock, irqflags); /* Going from 0->1 means we have to enable interrupts again */ if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) { @@ -975,6 +983,9 @@ void drm_vblank_put(struct drm_device *dev, int crtc) { BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0);
+ if (WARN_ON(crtc >= dev->num_crtcs)) + return; + /* Last user schedules interrupt disable */ if (atomic_dec_and_test(&dev->vblank[crtc].refcount) && (drm_vblank_offdelay > 0)) @@ -1019,6 +1030,9 @@ void drm_vblank_off(struct drm_device *dev, int crtc) unsigned long irqflags; unsigned int seq;
+ if (WARN_ON(crtc >= dev->num_crtcs)) + return; + spin_lock_irqsave(&dev->vbl_lock, irqflags); vblank_disable_and_save(dev, crtc); wake_up(&dev->vblank[crtc].queue); @@ -1078,6 +1092,9 @@ void drm_vblank_on(struct drm_device *dev, int crtc) { unsigned long irqflags;
+ if (WARN_ON(crtc >= dev->num_crtcs)) + return; + spin_lock_irqsave(&dev->vbl_lock, irqflags); /* re-enable interrupts if there's are users left */ if (atomic_read(&dev->vblank[crtc].refcount) != 0) @@ -1131,6 +1148,10 @@ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) /* vblank is not initialized (IRQ not installed ?), or has been freed */ if (!dev->num_crtcs) return; + + if (WARN_ON(crtc >= dev->num_crtcs)) + return; + /* * To avoid all the problems that might happen if interrupts * were enabled/disabled around or between these calls, we just @@ -1439,6 +1460,9 @@ bool drm_handle_vblank(struct drm_device *dev, int crtc) if (!dev->num_crtcs) return false;
+ if (WARN_ON(crtc >= dev->num_crtcs)) + return false; + /* Need timestamp lock to prevent concurrent execution with * vblank enable/disable, as this would cause inconsistent * or corrupted timestamps and vblank counts.