[PATCH v2 1/3] drm/amdgpu: svm check hmm range kzalloc return NULL

[Philip Yang]

Add hmm_range kzalloc return NULL error check. In case the get_pages
return failed, free and set hmm_range to NULL, to avoid double free in
get_pages_done.

Fixes: 29e6f5716115 ("drm/amdgpu: use user provided hmm_range buffer in 
amdgpu_ttm_tt_get_user_pages")
Signed-off-by: Philip Yang <philip.y...@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 8c3787b00f36..e8a15751c125 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1736,15 +1736,20 @@ static int svm_range_validate_and_map(struct mm_struct 
*mm,
                                continue;
                        }
 
-                       WRITE_ONCE(p->svms.faulting_task, current);
                        hmm_range = kzalloc(sizeof(*hmm_range), GFP_KERNEL);
-                       r = amdgpu_hmm_range_get_pages(&prange->notifier, addr, 
npages,
-                                                      readonly, owner,
-                                                      hmm_range);
-                       WRITE_ONCE(p->svms.faulting_task, NULL);
-                       if (r) {
-                               kfree(hmm_range);
-                               pr_debug("failed %d to get svm range pages\n", 
r);
+                       if (unlikely(!hmm_range)) {
+                               r = -ENOMEM;
+                       } else {
+                               WRITE_ONCE(p->svms.faulting_task, current);
+                               r = 
amdgpu_hmm_range_get_pages(&prange->notifier, addr, npages,
+                                                              readonly, owner,
+                                                              hmm_range);
+                               WRITE_ONCE(p->svms.faulting_task, NULL);
+                               if (r) {
+                                       kfree(hmm_range);
+                                       hmm_range = NULL;
+                                       pr_debug("failed %d to get svm range 
pages\n", r);
+                               }
                        }
                } else {
                        r = -EFAULT;
-- 
2.49.0