Hi,
this commit in -next causes my KDE to get stuck while starting. I see only the splash screen. If I disable effects by alt-shift-f12, it continues.
I bisected it to this commit: commit 430440fce7da4ad52c2af06a04a5132e5d19faaf Author: Tejun Heo tj@kernel.org Date: Thu Feb 7 12:31:37 2013 +1100
drm: convert to idr_alloc()
More concretely to the change in drm_gem_flink_ioctl. If I revert solely that one, it works again. Maybe I'm blind, but I do not see why...
Well I see a bug in there, but that is not the root cause -- there is a missing call to idr_preload_end. Of course, that one only leaves preemption disabled forever.
What I tried with no effect is this: --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -453,7 +453,8 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data, spin_lock(&dev->object_name_lock); if (!obj->name) { ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT); - obj->name = ret; + if (ret >= 0) + obj->name = ret; args->name = (uint64_t) obj->name; spin_unlock(&dev->object_name_lock);
@@ -469,6 +470,7 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data, }
err: + idr_preload_end(); drm_gem_object_unreference_unlocked(obj); return ret; }
thanks,
Hello, Jiri.
On Tue, Feb 12, 2013 at 10:55:37PM +0100, Jiri Slaby wrote:
this commit in -next causes my KDE to get stuck while starting. I see only the splash screen. If I disable effects by alt-shift-f12, it continues.
I bisected it to this commit: commit 430440fce7da4ad52c2af06a04a5132e5d19faaf Author: Tejun Heo tj@kernel.org Date: Thu Feb 7 12:31:37 2013 +1100
drm: convert to idr_alloc()More concretely to the change in drm_gem_flink_ioctl. If I revert solely that one, it works again. Maybe I'm blind, but I do not see why...
Well I see a bug in there, but that is not the root cause -- there is a missing call to idr_preload_end. Of course, that one only leaves preemption disabled forever.
Fix for this bug is already queued in -mm.
http://article.gmane.org/gmane.linux.kernel/1439101/raw
But you're saying that adding the missing idr_preload_end() doesn't make the problem go away, right?
Thanks.
On 02/12/2013 10:58 PM, Tejun Heo wrote:
Hello, Jiri.
On Tue, Feb 12, 2013 at 10:55:37PM +0100, Jiri Slaby wrote:
this commit in -next causes my KDE to get stuck while starting. I see only the splash screen. If I disable effects by alt-shift-f12, it continues.
I bisected it to this commit: commit 430440fce7da4ad52c2af06a04a5132e5d19faaf Author: Tejun Heo tj@kernel.org Date: Thu Feb 7 12:31:37 2013 +1100
drm: convert to idr_alloc()More concretely to the change in drm_gem_flink_ioctl. If I revert solely that one, it works again. Maybe I'm blind, but I do not see why...
Well I see a bug in there, but that is not the root cause -- there is a missing call to idr_preload_end. Of course, that one only leaves preemption disabled forever.
Fix for this bug is already queued in -mm.
http://article.gmane.org/gmane.linux.kernel/1439101/raw
But you're saying that adding the missing idr_preload_end() doesn't make the problem go away, right?
Yeah, right. I had to revert the whole hunk...
On 02/12/2013 10:55 PM, Jiri Slaby wrote:
--- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -453,7 +453,8 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data, spin_lock(&dev->object_name_lock); if (!obj->name) { ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
obj->name = ret;
if (ret >= 0)obj->name = ret; args->name = (uint64_t) obj->name; spin_unlock(&dev->object_name_lock);@@ -469,6 +470,7 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data, }
err:
idr_preload_end(); drm_gem_object_unreference_unlocked(obj); return ret;
Oh my, maybe: return ret < 0 ? ret : 0... Let's try.
On 02/12/2013 11:03 PM, Jiri Slaby wrote:
On 02/12/2013 10:55 PM, Jiri Slaby wrote:
--- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -453,7 +453,8 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data, spin_lock(&dev->object_name_lock); if (!obj->name) { ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
obj->name = ret;
if (ret >= 0)obj->name = ret; args->name = (uint64_t) obj->name; spin_unlock(&dev->object_name_lock);@@ -469,6 +470,7 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data, }
err:
idr_preload_end(); drm_gem_object_unreference_unlocked(obj); return ret;Oh my, maybe: return ret < 0 ? ret : 0... Let's try.
Bull's eye.
--- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -459,6 +459,7 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data,
if (ret < 0) goto err; + ret = 0;
/* Allocate a reference for the name table. */ drm_gem_object_reference(obj);
Hello, Jiri.
On Tue, Feb 12, 2013 at 11:08:41PM +0100, Jiri Slaby wrote:
Oh my, maybe: return ret < 0 ? ret : 0... Let's try.
Bull's eye.
Aieee....
--- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -459,6 +459,7 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data,
if (ret < 0) goto err;
ret = 0; /* Allocate a reference for the name table. */ drm_gem_object_reference(obj);
Care to write up a proper patch w/ SOB?
Thanks!
dri-devel@lists.freedesktop.org
-
Jiri Slaby -
Tejun Heo