On Wed, May 15, 2019 at 10:11:34AM +0100, Lionel Landwerlin wrote:
On 14/05/2019 19:14, Umesh Nerlige Ramappa wrote:
On Tue, May 14, 2019 at 10:34:49AM +0100, Lionel Landwerlin wrote:
Hi Umesh,
I just noticed this different between v1 & v2.
My understanding is that if destroy() is called, stream should be
the same as dev_priv->perf.exclusive_stream.
If it's not it sounds like a bug. So why change this?
v2 fixes only checkpatch warnings. it warned on use of BUG_ON.
BUG_ON is intended to crash the system in severe cases where the
driver/kernel is unusable. In this case, the mismatch between user
passed information and exclusive_stream may not require a crash.
This is called from i915_perf_release() which is attached to the
i915-perf file descriptor only in i915_perf.c.
If we managed to reach that function it must be because the file
descriptor given by userspace is associated to the i915-perf stream.
Having stream != dev_priv->perf.exclusive_stream means that we
probably screwed up the locking somewhere in this file.
So I would argue this is a kernel issue, not a user issue and that
using BUG_ON() is justified.
I see. Will change it back.
Thanks,
Umesh
Thanks,
-Lionel
-Lionel
On 03/05/2019 00:13, Umesh Nerlige Ramappa wrote:
static void i915_oa_stream_destroy(struct i915_perf_stream *stream)
{
struct drm_i915_private *dev_priv = stream->dev_priv;
- BUG_ON(stream != dev_priv->perf.oa.exclusive_stream);
+ if (stream != dev_priv->perf.exclusive_stream) {
+ WARN_ON_ONCE(stream != dev_priv->perf.exclusive_stream);
+ return;
+ }
/*
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