Re: [PATCH v2] drm/amdkfd: Fix potential deallocation of previously deallocated memory.

[Felix Kuehling]

On 2023-05-11 07:23, Daniil Dulov wrote:

Pointer mqd_mem_obj can be deallocated in kfd_gtt_sa_allocate().
The function then returns non-zero value, which causes the second deallocation.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
Signed-off-by: Daniil Dulov <d.du...@aladdin.ru>

Thanks. I am applying this patch to amd-staging-drm-next.

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

---
v2: Move if (retval) inside previous if as Andi Shyti 
<andi.sh...@linux.intel.com> suggested.
  drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 13 +++++++------
  1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
index 3b6f5963180d..dadeb2013fd9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
@@ -113,18 +113,19 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev 
*kfd,
                        &(mqd_mem_obj->gtt_mem),
                        &(mqd_mem_obj->gpu_addr),
                        (void *)&(mqd_mem_obj->cpu_ptr), true);
+
+               if (retval) {
+                       kfree(mqd_mem_obj);
+                       return NULL;
+               }
        } else {
                retval = kfd_gtt_sa_allocate(kfd, sizeof(struct v9_mqd),
                                &mqd_mem_obj);
-       }
-
-       if (retval) {
-               kfree(mqd_mem_obj);
-               return NULL;
+               if (retval)
+                       return NULL;
        }

return mqd_mem_obj;

-
  }

static void init_mqd(struct mqd_manager *mm, void **mqd,