[PATCH v2 1/1] drm/amdkfd: Create file descriptor after client is added to smi_clients list

[PATCH v2 1/1] drm/amdkfd: Create file descriptor after client is added to smi_clients list

[Lee Jones]

This ensures userspace cannot prematurely clean-up the client before
it is fully initialised which has been proven to cause issues in the
past.

Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---

CAVEAT: This patch is completely untested
        I can't seem to find a configuration strategy to compile test this
        allyesconfig and allmodconfig do not appear sufficient

v2: Also remove Client from RCU list in error path

 drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 24 +++++++++++++--------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
index e4beebb1c80a2..f2e1d506ba211 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
@@ -247,15 +247,6 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
 		return ret;
 	}
 
-	ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
-			       O_RDWR);
-	if (ret < 0) {
-		kfifo_free(&client->fifo);
-		kfree(client);
-		return ret;
-	}
-	*fd = ret;
-
 	init_waitqueue_head(&client->wait_queue);
 	spin_lock_init(&client->lock);
 	client->events = 0;
@@ -265,5 +256,20 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
 	list_add_rcu(&client->list, &dev->smi_clients);
 	spin_unlock(&dev->smi_lock);
 
+	ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
+			       O_RDWR);
+	if (ret < 0) {
+		spin_lock(&dev->smi_lock);
+		list_del_rcu(&client->list);
+		spin_unlock(&dev->smi_lock);
+
+		synchronize_rcu();
+
+		kfifo_free(&client->fifo);
+		kfree(client);
+		return ret;
+	}
+	*fd = ret;
+
 	return 0;
 }
-- 
2.35.1.1021.g381101b075-goog

Re: [PATCH v2 1/1] drm/amdkfd: Create file descriptor after client is added to smi_clients list

[Lee Jones]

On Fri, 01 Apr 2022, Lee Jones wrote:

> This ensures userspace cannot prematurely clean-up the client before
> it is fully initialised which has been proven to cause issues in the
> past.
> 
> Cc: Felix Kuehling <Felix.Kuehling@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: amd-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
> 
> CAVEAT: This patch is completely untested
>         I can't seem to find a configuration strategy to compile test this
>         allyesconfig and allmodconfig do not appear sufficient
> 
> v2: Also remove Client from RCU list in error path
> 
>  drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 24 +++++++++++++--------
>  1 file changed, 15 insertions(+), 9 deletions(-)

Please ignore this re-submission, script error.

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v2 1/1] drm/amdkfd: Create file descriptor after client is added to smi_clients list

[Lee Jones]

On Thu, 31 Mar 2022, Felix Kuehling wrote:

> 
> Am 2022-03-31 um 08:21 schrieb Lee Jones:
> > This ensures userspace cannot prematurely clean-up the client before
> > it is fully initialised which has been proven to cause issues in the
> > past.
> > 
> > Cc: Felix Kuehling <Felix.Kuehling@amd.com>
> > Cc: Alex Deucher <alexander.deucher@amd.com>
> > Cc: "Christian König" <christian.koenig@amd.com>
> > Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: amd-gfx@lists.freedesktop.org
> > Cc: dri-devel@lists.freedesktop.org
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> 
> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
> 
> I will apply to patch to amd-staging-drm-next.
> 
> > ---
> > 
> > CAVEAT: This patch is completely untested
> >          I can't seem to find a configuration strategy to compile test this
> >          allyesconfig and allmodconfig do not appear sufficient
> 
> That's very strange. It should get compiled if CONFIG_HSA_AMD is
> enabled.

Okay, I figured it out.

Apparently you can't give 'drivers/gpu/drm/amd' as a build param.

'drivers/gpu/drm' works as I expect however.

> I will at least compile-test it before I submit.

Great, thank you.

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v2 1/1] drm/amdkfd: Create file descriptor after client is added to smi_clients list

[Felix Kuehling]

Am 2022-03-31 um 08:21 schrieb Lee Jones:
> This ensures userspace cannot prematurely clean-up the client before
> it is fully initialised which has been proven to cause issues in the
> past.
>
> Cc: Felix Kuehling <Felix.Kuehling@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: amd-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>

I will apply to patch to amd-staging-drm-next.

> ---
>
> CAVEAT: This patch is completely untested
>          I can't seem to find a configuration strategy to compile test this
>          allyesconfig and allmodconfig do not appear sufficient

That's very strange. It should get compiled if CONFIG_HSA_AMD is 
enabled. I will at least compile-test it before I submit.

Regards,
   Felix


>
> v2: Also remove Client from RCU list in error path
>
>   drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 24 +++++++++++++--------
>   1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> index e4beebb1c80a2..f2e1d506ba211 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> @@ -247,15 +247,6 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
>   		return ret;
>   	}
>   
> -	ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
> -			       O_RDWR);
> -	if (ret < 0) {
> -		kfifo_free(&client->fifo);
> -		kfree(client);
> -		return ret;
> -	}
> -	*fd = ret;
> -
>   	init_waitqueue_head(&client->wait_queue);
>   	spin_lock_init(&client->lock);
>   	client->events = 0;
> @@ -265,5 +256,20 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
>   	list_add_rcu(&client->list, &dev->smi_clients);
>   	spin_unlock(&dev->smi_lock);
>   
> +	ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
> +			       O_RDWR);
> +	if (ret < 0) {
> +		spin_lock(&dev->smi_lock);
> +		list_del_rcu(&client->list);
> +		spin_unlock(&dev->smi_lock);
> +
> +		synchronize_rcu();
> +
> +		kfifo_free(&client->fifo);
> +		kfree(client);
> +		return ret;
> +	}
> +	*fd = ret;
> +
>   	return 0;
>   }

[PATCH v2 1/1] drm/amdkfd: Create file descriptor after client is added to smi_clients list

[Lee Jones]

This ensures userspace cannot prematurely clean-up the client before
it is fully initialised which has been proven to cause issues in the
past.

Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---

CAVEAT: This patch is completely untested
        I can't seem to find a configuration strategy to compile test this
        allyesconfig and allmodconfig do not appear sufficient

v2: Also remove Client from RCU list in error path

 drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 24 +++++++++++++--------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
index e4beebb1c80a2..f2e1d506ba211 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
@@ -247,15 +247,6 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
 		return ret;
 	}
 
-	ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
-			       O_RDWR);
-	if (ret < 0) {
-		kfifo_free(&client->fifo);
-		kfree(client);
-		return ret;
-	}
-	*fd = ret;
-
 	init_waitqueue_head(&client->wait_queue);
 	spin_lock_init(&client->lock);
 	client->events = 0;
@@ -265,5 +256,20 @@ int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
 	list_add_rcu(&client->list, &dev->smi_clients);
 	spin_unlock(&dev->smi_lock);
 
+	ret = anon_inode_getfd(kfd_smi_name, &kfd_smi_ev_fops, (void *)client,
+			       O_RDWR);
+	if (ret < 0) {
+		spin_lock(&dev->smi_lock);
+		list_del_rcu(&client->list);
+		spin_unlock(&dev->smi_lock);
+
+		synchronize_rcu();
+
+		kfifo_free(&client->fifo);
+		kfree(client);
+		return ret;
+	}
+	*fd = ret;
+
 	return 0;
 }
-- 
2.35.1.1021.g381101b075-goog