From: Rob Clark <[email protected]>
gem_context_register() makes the context visible to userspace, and which
point a separate thread can trigger the I915_GEM_CONTEXT_DESTROY ioctl.
So we need to ensure that nothing uses the ctx ptr after this. And we
need to ensure that adding the ctx to the xarray is the *last* thing
that gem_context_register() does with the ctx pointer.
Signed-off-by: Rob Clark <[email protected]>
---
drivers/gpu/drm/i915/gem/i915_gem_context.c | 24 +++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 7f2831efc798..6250de9b9196 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -1688,6 +1688,10 @@ void i915_gem_init__contexts(struct drm_i915_private *i915)
init_contexts(&i915->gem.contexts);
}
+/*
+ * Note that this implicitly consumes the ctx reference, by placing
+ * the ctx in the context_xa.
+ */
static void gem_context_register(struct i915_gem_context *ctx,
struct drm_i915_file_private *fpriv,
u32 id)
@@ -1703,10 +1707,6 @@ static void gem_context_register(struct i915_gem_context *ctx,
snprintf(ctx->name, sizeof(ctx->name), "%s[%d]",
current->comm, pid_nr(ctx->pid));
- /* And finally expose ourselves to userspace via the idr */
- old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
- WARN_ON(old);
-
spin_lock(&ctx->client->ctx_lock);
list_add_tail_rcu(&ctx->client_link, &ctx->client->ctx_list);
spin_unlock(&ctx->client->ctx_lock);
@@ -1714,6 +1714,10 @@ static void gem_context_register(struct i915_gem_context *ctx,
spin_lock(&i915->gem.contexts.lock);
list_add_tail(&ctx->link, &i915->gem.contexts.list);
spin_unlock(&i915->gem.contexts.lock);
+
+ /* And finally expose ourselves to userspace via the idr */
+ old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
+ WARN_ON(old);
}
int i915_gem_context_open(struct drm_i915_private *i915,
@@ -2199,14 +2203,22 @@ finalize_create_context_locked(struct drm_i915_file_private *file_priv,
if (IS_ERR(ctx))
return ctx;
+ /*
+ * One for the xarray and one for the caller. We need to grab
+ * the reference *prior* to making the ctx visble to userspace
+ * in gem_context_register(), as at any point after that
+ * userspace can try to race us with another thread destroying
+ * the context under our feet.
+ */
+ i915_gem_context_get(ctx);
+
gem_context_register(ctx, file_priv, id);
old = xa_erase(&file_priv->proto_context_xa, id);
GEM_BUG_ON(old != pc);
proto_context_close(file_priv->dev_priv, pc);
- /* One for the xarray and one for the caller */
- return i915_gem_context_get(ctx);
+ return ctx;
}
struct i915_gem_context *
--
2.38.1
On 03/01/2023 23:49, Rob Clark wrote:
> From: Rob Clark <[email protected]>
>
> gem_context_register() makes the context visible to userspace, and which
> point a separate thread can trigger the I915_GEM_CONTEXT_DESTROY ioctl.
> So we need to ensure that nothing uses the ctx ptr after this. And we
> need to ensure that adding the ctx to the xarray is the *last* thing
> that gem_context_register() does with the ctx pointer.
Any backtraces from oopses or notes on how it was found to record in the commit message?
> Signed-off-by: Rob Clark <[email protected]>
Fixes: a4c1cdd34e2c ("drm/i915/gem: Delay context creation (v3)")
References: 3aa9945a528e ("drm/i915: Separate GEM context construction and registration to userspace")
Cc: <[email protected]> # v5.15+
> ---
> drivers/gpu/drm/i915/gem/i915_gem_context.c | 24 +++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index 7f2831efc798..6250de9b9196 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -1688,6 +1688,10 @@ void i915_gem_init__contexts(struct drm_i915_private *i915)
> init_contexts(&i915->gem.contexts);
> }
>
> +/*
> + * Note that this implicitly consumes the ctx reference, by placing
> + * the ctx in the context_xa.
> + */
> static void gem_context_register(struct i915_gem_context *ctx,
> struct drm_i915_file_private *fpriv,
> u32 id)
> @@ -1703,10 +1707,6 @@ static void gem_context_register(struct i915_gem_context *ctx,
> snprintf(ctx->name, sizeof(ctx->name), "%s[%d]",
> current->comm, pid_nr(ctx->pid));
>
> - /* And finally expose ourselves to userspace via the idr */
> - old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
> - WARN_ON(old);
> -
> spin_lock(&ctx->client->ctx_lock);
> list_add_tail_rcu(&ctx->client_link, &ctx->client->ctx_list);
> spin_unlock(&ctx->client->ctx_lock);
> @@ -1714,6 +1714,10 @@ static void gem_context_register(struct i915_gem_context *ctx,
> spin_lock(&i915->gem.contexts.lock);
> list_add_tail(&ctx->link, &i915->gem.contexts.list);
> spin_unlock(&i915->gem.contexts.lock);
> +
> + /* And finally expose ourselves to userspace via the idr */
> + old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
> + WARN_ON(old);
Have you seen that this hunk is needed or just moving it for a good measure? To be clear, it is probably best to move it even if the current placement cannot cause any problems, I am just double-checking if you had any concrete observations here while mulling over easier stable backports if we would omit it.
> }
>
> int i915_gem_context_open(struct drm_i915_private *i915,
> @@ -2199,14 +2203,22 @@ finalize_create_context_locked(struct drm_i915_file_private *file_priv,
> if (IS_ERR(ctx))
> return ctx;
>
> + /*
> + * One for the xarray and one for the caller. We need to grab
> + * the reference *prior* to making the ctx visble to userspace
> + * in gem_context_register(), as at any point after that
> + * userspace can try to race us with another thread destroying
> + * the context under our feet.
> + */
> + i915_gem_context_get(ctx);
> +
> gem_context_register(ctx, file_priv, id);
>
> old = xa_erase(&file_priv->proto_context_xa, id);
> GEM_BUG_ON(old != pc);
> proto_context_close(file_priv->dev_priv, pc);
>
> - /* One for the xarray and one for the caller */
> - return i915_gem_context_get(ctx);
> + return ctx;
Otherwise userspace can look up a context which hasn't had it's reference count increased yep. I can add the Fixes: and Stable: tags while merging if no complaints.
Reviewed-by: Tvrtko Ursulin <[email protected]>
Regards,
Tvrtko
> }
>
> struct i915_gem_context *
On Wed, Jan 4, 2023 at 1:34 AM Tvrtko Ursulin
<[email protected]> wrote:
>
>
> On 03/01/2023 23:49, Rob Clark wrote:
> > From: Rob Clark <[email protected]>
> >
> > gem_context_register() makes the context visible to userspace, and which
> > point a separate thread can trigger the I915_GEM_CONTEXT_DESTROY ioctl.
> > So we need to ensure that nothing uses the ctx ptr after this. And we
> > need to ensure that adding the ctx to the xarray is the *last* thing
> > that gem_context_register() does with the ctx pointer.
>
> Any backtraces from oopses or notes on how it was found to record in the commit message?
It was a UAF bug that was reported to us
https://bugs.chromium.org/p/chromium/issues/detail?id=1401594 (but I
guess security bugs are not going to be visible)
>
> > Signed-off-by: Rob Clark <[email protected]>
>
> Fixes: a4c1cdd34e2c ("drm/i915/gem: Delay context creation (v3)")
> References: 3aa9945a528e ("drm/i915: Separate GEM context construction and registration to userspace")
> Cc: <[email protected]> # v5.15+
>
> > ---
> > drivers/gpu/drm/i915/gem/i915_gem_context.c | 24 +++++++++++++++------
> > 1 file changed, 18 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > index 7f2831efc798..6250de9b9196 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > @@ -1688,6 +1688,10 @@ void i915_gem_init__contexts(struct drm_i915_private *i915)
> > init_contexts(&i915->gem.contexts);
> > }
> >
> > +/*
> > + * Note that this implicitly consumes the ctx reference, by placing
> > + * the ctx in the context_xa.
> > + */
> > static void gem_context_register(struct i915_gem_context *ctx,
> > struct drm_i915_file_private *fpriv,
> > u32 id)
> > @@ -1703,10 +1707,6 @@ static void gem_context_register(struct i915_gem_context *ctx,
> > snprintf(ctx->name, sizeof(ctx->name), "%s[%d]",
> > current->comm, pid_nr(ctx->pid));
> >
> > - /* And finally expose ourselves to userspace via the idr */
> > - old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
> > - WARN_ON(old);
> > -
> > spin_lock(&ctx->client->ctx_lock);
> > list_add_tail_rcu(&ctx->client_link, &ctx->client->ctx_list);
> > spin_unlock(&ctx->client->ctx_lock);
> > @@ -1714,6 +1714,10 @@ static void gem_context_register(struct i915_gem_context *ctx,
> > spin_lock(&i915->gem.contexts.lock);
> > list_add_tail(&ctx->link, &i915->gem.contexts.list);
> > spin_unlock(&i915->gem.contexts.lock);
> > +
> > + /* And finally expose ourselves to userspace via the idr */
> > + old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
> > + WARN_ON(old);
>
> Have you seen that this hunk is needed or just moving it for a good measure? To be clear, it is probably best to move it even if the current placement cannot cause any problems, I am just double-checking if you had any concrete observations here while mulling over easier stable backports if we would omit it.
>
This was actually the originally reported issue, the
finalize_create_context_locked() part was something I found when the
original report prompted me to audit gem_context_register() call
paths.
> > }
> >
> > int i915_gem_context_open(struct drm_i915_private *i915,
> > @@ -2199,14 +2203,22 @@ finalize_create_context_locked(struct drm_i915_file_private *file_priv,
> > if (IS_ERR(ctx))
> > return ctx;
> >
> > + /*
> > + * One for the xarray and one for the caller. We need to grab
> > + * the reference *prior* to making the ctx visble to userspace
> > + * in gem_context_register(), as at any point after that
> > + * userspace can try to race us with another thread destroying
> > + * the context under our feet.
> > + */
> > + i915_gem_context_get(ctx);
> > +
> > gem_context_register(ctx, file_priv, id);
> >
> > old = xa_erase(&file_priv->proto_context_xa, id);
> > GEM_BUG_ON(old != pc);
> > proto_context_close(file_priv->dev_priv, pc);
> >
> > - /* One for the xarray and one for the caller */
> > - return i915_gem_context_get(ctx);
> > + return ctx;
>
> Otherwise userspace can look up a context which hasn't had it's reference count increased yep. I can add the Fixes: and Stable: tags while merging if no complaints.
>
> Reviewed-by: Tvrtko Ursulin <[email protected]>
Thanks
BR,
-R
>
> Regards,
>
> Tvrtko
>
> > }
> >
> > struct i915_gem_context *
On 05/01/2023 15:52, Andi Shyti wrote:
> Hi Rob,
>
> On Tue, Jan 03, 2023 at 03:49:46PM -0800, Rob Clark wrote:
>> From: Rob Clark <[email protected]>
>>
>> gem_context_register() makes the context visible to userspace, and which
>> point a separate thread can trigger the I915_GEM_CONTEXT_DESTROY ioctl.
>> So we need to ensure that nothing uses the ctx ptr after this. And we
>> need to ensure that adding the ctx to the xarray is the *last* thing
>> that gem_context_register() does with the ctx pointer.
>>
>> Signed-off-by: Rob Clark <[email protected]>
>
> Reviewed-by: Andi Shyti <[email protected]>
>
> I also agree with Tvrtko that we should add Stable: and Fixes:.
Yeah I'll add them all when merging. Just waiting for full CI results. It will be like this:
Fixes: eb4dedae920a ("drm/i915/gem: Delay tracking the GEM context until it is registered")
Fixes: a4c1cdd34e2c ("drm/i915/gem: Delay context creation (v3)")
Fixes: 49bd54b390c2 ("drm/i915: Track all user contexts per client")
Cc: <[email protected]> # v5.10+
Regards,
Tvrtko
> One little thing, "user after free" is clearer that UAF :)
>
> Thanks,
> Andi
>
>> ---
>> drivers/gpu/drm/i915/gem/i915_gem_context.c | 24 +++++++++++++++------
>> 1 file changed, 18 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> index 7f2831efc798..6250de9b9196 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> @@ -1688,6 +1688,10 @@ void i915_gem_init__contexts(struct drm_i915_private *i915)
>> init_contexts(&i915->gem.contexts);
>> }
>>
>> +/*
>> + * Note that this implicitly consumes the ctx reference, by placing
>> + * the ctx in the context_xa.
>> + */
>> static void gem_context_register(struct i915_gem_context *ctx,
>> struct drm_i915_file_private *fpriv,
>> u32 id)
>> @@ -1703,10 +1707,6 @@ static void gem_context_register(struct i915_gem_context *ctx,
>> snprintf(ctx->name, sizeof(ctx->name), "%s[%d]",
>> current->comm, pid_nr(ctx->pid));
>>
>> - /* And finally expose ourselves to userspace via the idr */
>> - old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
>> - WARN_ON(old);
>> -
>> spin_lock(&ctx->client->ctx_lock);
>> list_add_tail_rcu(&ctx->client_link, &ctx->client->ctx_list);
>> spin_unlock(&ctx->client->ctx_lock);
>> @@ -1714,6 +1714,10 @@ static void gem_context_register(struct i915_gem_context *ctx,
>> spin_lock(&i915->gem.contexts.lock);
>> list_add_tail(&ctx->link, &i915->gem.contexts.list);
>> spin_unlock(&i915->gem.contexts.lock);
>> +
>> + /* And finally expose ourselves to userspace via the idr */
>> + old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
>> + WARN_ON(old);
>> }
>>
>> int i915_gem_context_open(struct drm_i915_private *i915,
>> @@ -2199,14 +2203,22 @@ finalize_create_context_locked(struct drm_i915_file_private *file_priv,
>> if (IS_ERR(ctx))
>> return ctx;
>>
>> + /*
>> + * One for the xarray and one for the caller. We need to grab
>> + * the reference *prior* to making the ctx visble to userspace
>> + * in gem_context_register(), as at any point after that
>> + * userspace can try to race us with another thread destroying
>> + * the context under our feet.
>> + */
>> + i915_gem_context_get(ctx);
>> +
>> gem_context_register(ctx, file_priv, id);
>>
>> old = xa_erase(&file_priv->proto_context_xa, id);
>> GEM_BUG_ON(old != pc);
>> proto_context_close(file_priv->dev_priv, pc);
>>
>> - /* One for the xarray and one for the caller */
>> - return i915_gem_context_get(ctx);
>> + return ctx;
>> }
>>
>> struct i915_gem_context *
>> --
>> 2.38.1
Hi Rob,
On Tue, Jan 03, 2023 at 03:49:46PM -0800, Rob Clark wrote:
> From: Rob Clark <[email protected]>
>
> gem_context_register() makes the context visible to userspace, and which
> point a separate thread can trigger the I915_GEM_CONTEXT_DESTROY ioctl.
> So we need to ensure that nothing uses the ctx ptr after this. And we
> need to ensure that adding the ctx to the xarray is the *last* thing
> that gem_context_register() does with the ctx pointer.
>
> Signed-off-by: Rob Clark <[email protected]>
Reviewed-by: Andi Shyti <[email protected]>
I also agree with Tvrtko that we should add Stable: and Fixes:.
One little thing, "user after free" is clearer that UAF :)
Thanks,
Andi
> ---
> drivers/gpu/drm/i915/gem/i915_gem_context.c | 24 +++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index 7f2831efc798..6250de9b9196 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -1688,6 +1688,10 @@ void i915_gem_init__contexts(struct drm_i915_private *i915)
> init_contexts(&i915->gem.contexts);
> }
>
> +/*
> + * Note that this implicitly consumes the ctx reference, by placing
> + * the ctx in the context_xa.
> + */
> static void gem_context_register(struct i915_gem_context *ctx,
> struct drm_i915_file_private *fpriv,
> u32 id)
> @@ -1703,10 +1707,6 @@ static void gem_context_register(struct i915_gem_context *ctx,
> snprintf(ctx->name, sizeof(ctx->name), "%s[%d]",
> current->comm, pid_nr(ctx->pid));
>
> - /* And finally expose ourselves to userspace via the idr */
> - old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
> - WARN_ON(old);
> -
> spin_lock(&ctx->client->ctx_lock);
> list_add_tail_rcu(&ctx->client_link, &ctx->client->ctx_list);
> spin_unlock(&ctx->client->ctx_lock);
> @@ -1714,6 +1714,10 @@ static void gem_context_register(struct i915_gem_context *ctx,
> spin_lock(&i915->gem.contexts.lock);
> list_add_tail(&ctx->link, &i915->gem.contexts.list);
> spin_unlock(&i915->gem.contexts.lock);
> +
> + /* And finally expose ourselves to userspace via the idr */
> + old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
> + WARN_ON(old);
> }
>
> int i915_gem_context_open(struct drm_i915_private *i915,
> @@ -2199,14 +2203,22 @@ finalize_create_context_locked(struct drm_i915_file_private *file_priv,
> if (IS_ERR(ctx))
> return ctx;
>
> + /*
> + * One for the xarray and one for the caller. We need to grab
> + * the reference *prior* to making the ctx visble to userspace
> + * in gem_context_register(), as at any point after that
> + * userspace can try to race us with another thread destroying
> + * the context under our feet.
> + */
> + i915_gem_context_get(ctx);
> +
> gem_context_register(ctx, file_priv, id);
>
> old = xa_erase(&file_priv->proto_context_xa, id);
> GEM_BUG_ON(old != pc);
> proto_context_close(file_priv->dev_priv, pc);
>
> - /* One for the xarray and one for the caller */
> - return i915_gem_context_get(ctx);
> + return ctx;
> }
>
> struct i915_gem_context *
> --
> 2.38.1
On 05/01/2023 16:00, Tvrtko Ursulin wrote:
>
> On 05/01/2023 15:52, Andi Shyti wrote:
>> Hi Rob,
>>
>> On Tue, Jan 03, 2023 at 03:49:46PM -0800, Rob Clark wrote:
>>> From: Rob Clark <[email protected]>
>>>
>>> gem_context_register() makes the context visible to userspace, and which
>>> point a separate thread can trigger the I915_GEM_CONTEXT_DESTROY ioctl.
>>> So we need to ensure that nothing uses the ctx ptr after this. And we
>>> need to ensure that adding the ctx to the xarray is the *last* thing
>>> that gem_context_register() does with the ctx pointer.
>>>
>>> Signed-off-by: Rob Clark <[email protected]>
>>
>> Reviewed-by: Andi Shyti <[email protected]>
>>
>> I also agree with Tvrtko that we should add Stable: and Fixes:.
>
> Yeah I'll add them all when merging. Just waiting for full CI results.
> It will be like this:
>
> Fixes: eb4dedae920a ("drm/i915/gem: Delay tracking the GEM context until
> it is registered")
> Fixes: a4c1cdd34e2c ("drm/i915/gem: Delay context creation (v3)")
> Fixes: 49bd54b390c2 ("drm/i915: Track all user contexts per client")
> Cc: <[email protected]> # v5.10+
Pushed to drm-intel-gt-next - thanks for the fix and reviews.
Regards,
Tvrtko
>
> Regards,
>
> Tvrtko
>
>> One little thing, "user after free" is clearer that UAF :)
>>
>> Thanks,
>> Andi
>>
>>> ---
>>> drivers/gpu/drm/i915/gem/i915_gem_context.c | 24 +++++++++++++++------
>>> 1 file changed, 18 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> index 7f2831efc798..6250de9b9196 100644
>>> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> @@ -1688,6 +1688,10 @@ void i915_gem_init__contexts(struct
>>> drm_i915_private *i915)
>>> init_contexts(&i915->gem.contexts);
>>> }
>>> +/*
>>> + * Note that this implicitly consumes the ctx reference, by placing
>>> + * the ctx in the context_xa.
>>> + */
>>> static void gem_context_register(struct i915_gem_context *ctx,
>>> struct drm_i915_file_private *fpriv,
>>> u32 id)
>>> @@ -1703,10 +1707,6 @@ static void gem_context_register(struct
>>> i915_gem_context *ctx,
>>> snprintf(ctx->name, sizeof(ctx->name), "%s[%d]",
>>> current->comm, pid_nr(ctx->pid));
>>> - /* And finally expose ourselves to userspace via the idr */
>>> - old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
>>> - WARN_ON(old);
>>> -
>>> spin_lock(&ctx->client->ctx_lock);
>>> list_add_tail_rcu(&ctx->client_link, &ctx->client->ctx_list);
>>> spin_unlock(&ctx->client->ctx_lock);
>>> @@ -1714,6 +1714,10 @@ static void gem_context_register(struct
>>> i915_gem_context *ctx,
>>> spin_lock(&i915->gem.contexts.lock);
>>> list_add_tail(&ctx->link, &i915->gem.contexts.list);
>>> spin_unlock(&i915->gem.contexts.lock);
>>> +
>>> + /* And finally expose ourselves to userspace via the idr */
>>> + old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
>>> + WARN_ON(old);
>>> }
>>> int i915_gem_context_open(struct drm_i915_private *i915,
>>> @@ -2199,14 +2203,22 @@ finalize_create_context_locked(struct
>>> drm_i915_file_private *file_priv,
>>> if (IS_ERR(ctx))
>>> return ctx;
>>> + /*
>>> + * One for the xarray and one for the caller. We need to grab
>>> + * the reference *prior* to making the ctx visble to userspace
>>> + * in gem_context_register(), as at any point after that
>>> + * userspace can try to race us with another thread destroying
>>> + * the context under our feet.
>>> + */
>>> + i915_gem_context_get(ctx);
>>> +
>>> gem_context_register(ctx, file_priv, id);
>>> old = xa_erase(&file_priv->proto_context_xa, id);
>>> GEM_BUG_ON(old != pc);
>>> proto_context_close(file_priv->dev_priv, pc);
>>> - /* One for the xarray and one for the caller */
>>> - return i915_gem_context_get(ctx);
>>> + return ctx;
>>> }
>>> struct i915_gem_context *
>>> --
>>> 2.38.1