[patch 1/4] drm/amdgpu: unwind properly in amdgpu_cs_parser_init()
Alex Deucher
alexdeucher at gmail.com
Wed Sep 23 10:13:21 PDT 2015
On Wed, Sep 23, 2015 at 10:16 AM, Christian König
<christian.koenig at amd.com> wrote:
> On 23.09.2015 12:59, Dan Carpenter wrote:
>>
>> The amdgpu_cs_parser_init() function doesn't clean up after itself but
>> instead the caller uses a free everything function amdgpu_cs_parser_fini()
>> on failure. This style of error handling is often buggy. In this
>> example, we call "drm_free_large(parser->chunks[i].kdata);" when it is
>> an unintialized pointer or when "parser->chunks" is NULL.
>>
>> I fixed this bug by adding unwind code so that it frees everything that
>> it allocates.
>>
>> I also mode some other very minor changes:
>> 1) Renamed "r" to "ret".
>> 2) Moved the chunk_array allocation to the start of the function.
>> 3) Removed some initializers which are no longer needed.
>>
>> Reported-by: Ilja Van Sprundel <ivansprundel at ioactive.com>
>> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
>
>
> The whole set looks sane to me, patches are Reviewed-by: Christian König
> <christian.koenig at amd.com>
Applied. thanks!
Alex
>
> Regards,
> Christian.
>
>
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> index 3b355ae..abb257d 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> @@ -154,42 +154,41 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser
>> *p, void *data)
>> {
>> union drm_amdgpu_cs *cs = data;
>> uint64_t *chunk_array_user;
>> - uint64_t *chunk_array = NULL;
>> + uint64_t *chunk_array;
>> struct amdgpu_fpriv *fpriv = p->filp->driver_priv;
>> unsigned size, i;
>> - int r = 0;
>> + int ret;
>> - if (!cs->in.num_chunks)
>> - goto out;
>> + if (cs->in.num_chunks == 0)
>> + return 0;
>> +
>> + chunk_array = kmalloc_array(cs->in.num_chunks, sizeof(uint64_t),
>> GFP_KERNEL);
>> + if (!chunk_array)
>> + return -ENOMEM;
>> p->ctx = amdgpu_ctx_get(fpriv, cs->in.ctx_id);
>> if (!p->ctx) {
>> - r = -EINVAL;
>> - goto out;
>> + ret = -EINVAL;
>> + goto free_chunk;
>> }
>> +
>> p->bo_list = amdgpu_bo_list_get(fpriv, cs->in.bo_list_handle);
>> /* get chunks */
>> INIT_LIST_HEAD(&p->validated);
>> - chunk_array = kmalloc_array(cs->in.num_chunks, sizeof(uint64_t),
>> GFP_KERNEL);
>> - if (chunk_array == NULL) {
>> - r = -ENOMEM;
>> - goto out;
>> - }
>> -
>> chunk_array_user = (uint64_t __user *)(cs->in.chunks);
>> if (copy_from_user(chunk_array, chunk_array_user,
>> sizeof(uint64_t)*cs->in.num_chunks)) {
>> - r = -EFAULT;
>> - goto out;
>> + ret = -EFAULT;
>> + goto put_bo_list;
>> }
>> p->nchunks = cs->in.num_chunks;
>> p->chunks = kmalloc_array(p->nchunks, sizeof(struct
>> amdgpu_cs_chunk),
>> GFP_KERNEL);
>> - if (p->chunks == NULL) {
>> - r = -ENOMEM;
>> - goto out;
>> + if (!p->chunks) {
>> + ret = -ENOMEM;
>> + goto put_bo_list;
>> }
>> for (i = 0; i < p->nchunks; i++) {
>> @@ -200,8 +199,9 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p,
>> void *data)
>> chunk_ptr = (void __user *)chunk_array[i];
>> if (copy_from_user(&user_chunk, chunk_ptr,
>> sizeof(struct
>> drm_amdgpu_cs_chunk))) {
>> - r = -EFAULT;
>> - goto out;
>> + ret = -EFAULT;
>> + i--;
>> + goto free_partial_kdata;
>> }
>> p->chunks[i].chunk_id = user_chunk.chunk_id;
>> p->chunks[i].length_dw = user_chunk.length_dw;
>> @@ -212,13 +212,14 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser
>> *p, void *data)
>> p->chunks[i].kdata = drm_malloc_ab(size,
>> sizeof(uint32_t));
>> if (p->chunks[i].kdata == NULL) {
>> - r = -ENOMEM;
>> - goto out;
>> + ret = -ENOMEM;
>> + i--;
>> + goto free_partial_kdata;
>> }
>> size *= sizeof(uint32_t);
>> if (copy_from_user(p->chunks[i].kdata, cdata, size)) {
>> - r = -EFAULT;
>> - goto out;
>> + ret = -EFAULT;
>> + goto free_partial_kdata;
>> }
>> switch (p->chunks[i].chunk_id) {
>> @@ -238,15 +239,15 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser
>> *p, void *data)
>> gobj =
>> drm_gem_object_lookup(p->adev->ddev,
>> p->filp,
>> handle);
>> if (gobj == NULL) {
>> - r = -EINVAL;
>> - goto out;
>> + ret = -EINVAL;
>> + goto free_partial_kdata;
>> }
>> p->uf.bo = gem_to_amdgpu_bo(gobj);
>> p->uf.offset = fence_data->offset;
>> } else {
>> - r = -EINVAL;
>> - goto out;
>> + ret = -EINVAL;
>> + goto free_partial_kdata;
>> }
>> break;
>> @@ -254,19 +255,35 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser
>> *p, void *data)
>> break;
>> default:
>> - r = -EINVAL;
>> - goto out;
>> + ret = -EINVAL;
>> + goto free_partial_kdata;
>> }
>> }
>> p->ibs = kcalloc(p->num_ibs, sizeof(struct amdgpu_ib),
>> GFP_KERNEL);
>> - if (!p->ibs)
>> - r = -ENOMEM;
>> + if (!p->ibs) {
>> + ret = -ENOMEM;
>> + goto free_all_kdata;
>> + }
>> -out:
>> kfree(chunk_array);
>> - return r;
>> + return 0;
>> +
>> +free_all_kdata:
>> + i = p->nchunks - 1;
>> +free_partial_kdata:
>> + for (; i >= 0; i--)
>> + drm_free_large(p->chunks[i].kdata);
>> + kfree(p->chunks);
>> +put_bo_list:
>> + if (p->bo_list)
>> + amdgpu_bo_list_put(p->bo_list);
>> + amdgpu_ctx_put(p->ctx);
>> +free_chunk:
>> + kfree(chunk_array);
>> +
>> + return ret;
>> }
>> /* Returns how many bytes TTM can move per IB.
>> @@ -804,7 +821,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void
>> *data, struct drm_file *filp)
>> r = amdgpu_cs_parser_init(parser, data);
>> if (r) {
>> DRM_ERROR("Failed to initialize parser !\n");
>> - amdgpu_cs_parser_fini(parser, r, false);
>> + kfree(parser);
>> up_read(&adev->exclusive_lock);
>> r = amdgpu_cs_handle_lockup(adev, r);
>> return r;
>
>
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