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

[Philip Yang <Philip.Yang@amd.com>]

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.Yang@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