[PATCH 03/11] drm/v3d: Fix potential memory leak in the performance extension

Maíra Canal mcanal at igalia.com
Thu Jul 11 13:00:53 UTC 2024


On 7/11/24 06:15, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
> 
> If fetching of userspace memory fails during the main loop, all drm sync
> objs looked up until that point will be leaked because of the missing
> drm_syncobj_put.
> 
> Fix it by exporting and using a common cleanup helper.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
> Fixes: bae7cb5d6800 ("drm/v3d: Create a CPU job extension for the reset performance query job")
> Cc: Maíra Canal <mcanal at igalia.com>
> Cc: Iago Toral Quiroga <itoral at igalia.com>
> Cc: <stable at vger.kernel.org> # v6.8+
> ---
>   drivers/gpu/drm/v3d/v3d_drv.h    |  2 ++
>   drivers/gpu/drm/v3d/v3d_sched.c  | 22 ++++++++++----
>   drivers/gpu/drm/v3d/v3d_submit.c | 50 ++++++++++++++++++++------------
>   3 files changed, 49 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
> index e208ffdfba32..dd3ead4cb8bd 100644
> --- a/drivers/gpu/drm/v3d/v3d_drv.h
> +++ b/drivers/gpu/drm/v3d/v3d_drv.h
> @@ -565,6 +565,8 @@ void v3d_mmu_remove_ptes(struct v3d_bo *bo);
>   /* v3d_sched.c */
>   void v3d_timestamp_query_info_free(struct v3d_timestamp_query_info *query_info,
>   				   unsigned int count);
> +void v3d_performance_query_info_free(struct v3d_performance_query_info *query_info,
> +				     unsigned int count);
>   void v3d_job_update_stats(struct v3d_job *job, enum v3d_queue queue);
>   int v3d_sched_init(struct v3d_dev *v3d);
>   void v3d_sched_fini(struct v3d_dev *v3d);
> diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
> index 59dc0287dab9..5fbbee47c6b7 100644
> --- a/drivers/gpu/drm/v3d/v3d_sched.c
> +++ b/drivers/gpu/drm/v3d/v3d_sched.c
> @@ -87,20 +87,30 @@ v3d_timestamp_query_info_free(struct v3d_timestamp_query_info *query_info,
>   	}
>   }
>   
> +void
> +v3d_performance_query_info_free(struct v3d_performance_query_info *query_info,
> +				unsigned int count)
> +{
> +	if (query_info->queries) {
> +		unsigned int i;
> +
> +		for (i = 0; i < count; i++)
> +			drm_syncobj_put(query_info->queries[i].syncobj);
> +
> +		kvfree(query_info->queries);
> +	}
> +}
> +
>   static void
>   v3d_cpu_job_free(struct drm_sched_job *sched_job)
>   {
>   	struct v3d_cpu_job *job = to_cpu_job(sched_job);
> -	struct v3d_performance_query_info *performance_query = &job->performance_query;
>   
>   	v3d_timestamp_query_info_free(&job->timestamp_query,
>   				      job->timestamp_query.count);
>   
> -	if (performance_query->queries) {
> -		for (int i = 0; i < performance_query->count; i++)
> -			drm_syncobj_put(performance_query->queries[i].syncobj);
> -		kvfree(performance_query->queries);
> -	}
> +	v3d_performance_query_info_free(&job->performance_query,
> +					job->performance_query.count);
>   
>   	v3d_job_cleanup(&job->base);
>   }
> diff --git a/drivers/gpu/drm/v3d/v3d_submit.c b/drivers/gpu/drm/v3d/v3d_submit.c
> index 121bf1314b80..d626c8539b04 100644
> --- a/drivers/gpu/drm/v3d/v3d_submit.c
> +++ b/drivers/gpu/drm/v3d/v3d_submit.c
> @@ -640,6 +640,8 @@ v3d_get_cpu_reset_performance_params(struct drm_file *file_priv,
>   	u32 __user *syncs;
>   	u64 __user *kperfmon_ids;
>   	struct drm_v3d_reset_performance_query reset;
> +	unsigned int i, j;
> +	int err;
>   
>   	if (!job) {
>   		DRM_DEBUG("CPU job extension was attached to a GPU job.\n");
> @@ -668,39 +670,43 @@ v3d_get_cpu_reset_performance_params(struct drm_file *file_priv,
>   	syncs = u64_to_user_ptr(reset.syncs);
>   	kperfmon_ids = u64_to_user_ptr(reset.kperfmon_ids);
>   
> -	for (int i = 0; i < reset.count; i++) {
> +	for (i = 0; i < reset.count; i++) {
>   		u32 sync;
>   		u64 ids;
>   		u32 __user *ids_pointer;
>   		u32 id;
>   
>   		if (copy_from_user(&sync, syncs++, sizeof(sync))) {
> -			kvfree(job->performance_query.queries);
> -			return -EFAULT;
> +			err = -EFAULT;
> +			goto error;
>   		}
>   
> -		job->performance_query.queries[i].syncobj = drm_syncobj_find(file_priv, sync);
> -
>   		if (copy_from_user(&ids, kperfmon_ids++, sizeof(ids))) {
> -			kvfree(job->performance_query.queries);
> -			return -EFAULT;
> +			err = -EFAULT;
> +			goto error;
>   		}
>   
>   		ids_pointer = u64_to_user_ptr(ids);
>   
> -		for (int j = 0; j < reset.nperfmons; j++) {
> +		for (j = 0; j < reset.nperfmons; j++) {
>   			if (copy_from_user(&id, ids_pointer++, sizeof(id))) {
> -				kvfree(job->performance_query.queries);
> -				return -EFAULT;
> +				err = -EFAULT;
> +				goto error;
>   			}
>   
>   			job->performance_query.queries[i].kperfmon_ids[j] = id;
>   		}
> +
> +		job->performance_query.queries[i].syncobj = drm_syncobj_find(file_priv, sync);
>   	}
>   	job->performance_query.count = reset.count;
>   	job->performance_query.nperfmons = reset.nperfmons;
>   
>   	return 0;
> +
> +error:
> +	v3d_performance_query_info_free(&job->performance_query, i);
> +	return err;
>   }
>   
>   static int
> @@ -711,6 +717,8 @@ v3d_get_cpu_copy_performance_query_params(struct drm_file *file_priv,
>   	u32 __user *syncs;
>   	u64 __user *kperfmon_ids;
>   	struct drm_v3d_copy_performance_query copy;
> +	unsigned int i, j;
> +	int err;
>   
>   	if (!job) {
>   		DRM_DEBUG("CPU job extension was attached to a GPU job.\n");
> @@ -749,27 +757,27 @@ v3d_get_cpu_copy_performance_query_params(struct drm_file *file_priv,
>   		u32 id;
>   
>   		if (copy_from_user(&sync, syncs++, sizeof(sync))) {
> -			kvfree(job->performance_query.queries);
> -			return -EFAULT;
> +			err = -EFAULT;
> +			goto error;
>   		}
>   
> -		job->performance_query.queries[i].syncobj = drm_syncobj_find(file_priv, sync);
> -
>   		if (copy_from_user(&ids, kperfmon_ids++, sizeof(ids))) {
> -			kvfree(job->performance_query.queries);
> -			return -EFAULT;
> +			err = -EFAULT;
> +			goto error;
>   		}
>   
>   		ids_pointer = u64_to_user_ptr(ids);
>   
> -		for (int j = 0; j < copy.nperfmons; j++) {
> +		for (j = 0; j < copy.nperfmons; j++) {
>   			if (copy_from_user(&id, ids_pointer++, sizeof(id))) {
> -				kvfree(job->performance_query.queries);
> -				return -EFAULT;
> +				err = -EFAULT;
> +				goto error;
>   			}
>   
>   			job->performance_query.queries[i].kperfmon_ids[j] = id;
>   		}
> +
> +		job->performance_query.queries[i].syncobj = drm_syncobj_find(file_priv, sync);
>   	}
>   	job->performance_query.count = copy.count;
>   	job->performance_query.nperfmons = copy.nperfmons;
> @@ -782,6 +790,10 @@ v3d_get_cpu_copy_performance_query_params(struct drm_file *file_priv,
>   	job->copy.stride = copy.stride;
>   
>   	return 0;
> +
> +error:
> +	v3d_performance_query_info_free(&job->performance_query, i);

I'm seeing this compiling warning from this patch:

drivers/gpu/drm/v3d/v3d_submit.c:860:59: warning: variable 'i' is 
uninitialized when used here [-Wuninitialized]
   860 | 
v3d_performance_query_info_free(&job->performance_query, i);
       |                                                                  ^
drivers/gpu/drm/v3d/v3d_submit.c:781:16: note: initialize the variable 
'i' to silence this warning
   781 |         unsigned int i, j;
       |                       ^
       |                        = 0
1 warning generated.

I believe that we are currently defining int i twice.

Best Regards,
- Maíra

> +	return err;
>   }
>   
>   /* Whenever userspace sets ioctl extensions, v3d_get_extensions parses data


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