Commit 709c3482 authored by Xiaogang Chen's avatar Xiaogang Chen Committed by Alex Deucher
Browse files

drm/amdkfd: Fix a race condition of vram buffer unref in svm code 



prange->svm_bo unref can happen in both mmu callback and a callback after
migrate to system ram. Both are async call in different tasks. Sync svm_bo
unref operation to avoid random "use-after-free".

Signed-off-by: default avatarXiaogang Chen <xiaogang.chen@amd.com>
Reviewed-by: default avatarPhilip Yang <Philip.Yang@amd.com>
Reviewed-by: default avatarJesse Zhang <Jesse.Zhang@amd.com>
Tested-by: default avatarJesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 003048dd

drivers/gpu/drm/amd/amdkfd/kfd_svm.c

+9 −2
Original line number Diff line number Diff line
@@ -637,8 +637,15 @@ svm_range_vram_node_new(struct kfd_node *node, struct svm_range *prange, 


void svm_range_vram_node_free(struct svm_range *prange)

{

	svm_range_bo_unref(prange->svm_bo);

	/* serialize prange->svm_bo unref */

	mutex_lock(&prange->lock);

	/* prange->svm_bo has not been unref */

	if (prange->ttm_res) {

		prange->ttm_res = NULL;

		mutex_unlock(&prange->lock);

		svm_range_bo_unref(prange->svm_bo);

	} else

		mutex_unlock(&prange->lock);

}



struct kfd_node *