On Thu, May 24, 2012 at 08:09:41PM +0200, Bruno Prémont wrote:
> I can easily trigger a crash in nouveau interrupt handler by unbinding
> and rebinding the GPU.
>
> The command used:
> echo $pci_device > nouveau/unbind && \
> sleep 5 && \
> echo $pci_device > nouveau/bind
>
>
> Kernel is 3.4.0 with modular drm/nouveau.
> GPU is NVidia nForce IGP (NV11)
>
>
> Unbinding seems to work fine, display switching back to VGA text mode.
> Rebinding the GPU slightly later causes the below trace:
>
> (...)
It crashed because Nouveau failed to disable vblank interrupt on unbind
and this interrupt triggered while drm was initializing vblank data.
Nouveau side was fixed by "drm/nv04/disp: disable vblank interrupts when
disabling display" by Ben Skeggs (3.5 merge window), drm side can be fixed
by this:
---
From: Marcin Slusarz <marcin.slusarz@xxxxxxxxx>
Subject: [PATCH] drm: do not expose vblank data before drm_vblank_init completes
It fixes oops in drm_handle_vblank when vblank interrupt triggers before
drm_vblank_init completes. Driver side should not let this happen, but let's
be on the safe side and handle this case.
Reported-by: Bruno Prémont <bonbons@xxxxxxxxxxxxxxxxx>
Tested-by: Bruno Prémont <bonbons@xxxxxxxxxxxxxxxxx>
Signed-off-by: Marcin Slusarz <marcin.slusarz@xxxxxxxxx>
---
drivers/gpu/drm/drm_irq.c | 21 +++++++++++++--------
1 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index c869436..7dda18c 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -183,12 +183,8 @@ static void vblank_disable_fn(unsigned long arg)
}
}
-void drm_vblank_cleanup(struct drm_device *dev)
+static void __drm_vblank_cleanup(struct drm_device *dev)
{
- /* Bail if the driver didn't call drm_vblank_init() */
- if (dev->num_crtcs == 0)
- return;
-
del_timer(&dev->vblank_disable_timer);
vblank_disable_fn((unsigned long)dev);
@@ -201,6 +197,15 @@ void drm_vblank_cleanup(struct drm_device *dev)
kfree(dev->last_vblank_wait);
kfree(dev->vblank_inmodeset);
kfree(dev->_vblank_time);
+}
+
+void drm_vblank_cleanup(struct drm_device *dev)
+{
+ /* Bail if the driver didn't call drm_vblank_init() */
+ if (dev->num_crtcs == 0)
+ return;
+
+ __drm_vblank_cleanup(dev);
dev->num_crtcs = 0;
}
@@ -215,8 +220,6 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs)
spin_lock_init(&dev->vbl_lock);
spin_lock_init(&dev->vblank_time_lock);
- dev->num_crtcs = num_crtcs;
-
dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs,
GFP_KERNEL);
if (!dev->vbl_queue)
@@ -268,10 +271,12 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs)
}
dev->vblank_disable_allowed = 0;
+ dev->num_crtcs = num_crtcs;
+
return 0;
err:
- drm_vblank_cleanup(dev);
+ __drm_vblank_cleanup(dev);
return ret;
}
EXPORT_SYMBOL(drm_vblank_init);
--
1.7.8.6
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