Here is a function call chain.
nvkm_vmm_pfn_map->nvkm_vmm_pfn_split_merge->nvkm_vmm_node_split
If nvkm_vma_tail return NULL in nvkm_vmm_node_split, it will
finally invoke nvkm_vmm_node_merge->nvkm_vmm_node_delete, which
will free the vma. However, nvkm_vmm_pfn_map didn't notice that.
It goes into next label and UAF happens.
Fix it by returning the return-value of nvkm_vmm_node_merge
instead of NULL.
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
---
drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
index ae793f400ba1..84d6fc87b2e8 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
@@ -937,8 +937,8 @@ nvkm_vmm_node_split(struct nvkm_vmm *vmm,
if (vma->size != size) {
struct nvkm_vma *tmp;
if (!(tmp = nvkm_vma_tail(vma, vma->size - size))) {
- nvkm_vmm_node_merge(vmm, prev, vma, NULL, vma->size);
- return NULL;
+ tmp = nvkm_vmm_node_merge(vmm, prev, vma, NULL, vma->size);
+ return tmp;
}
tmp->part = true;
nvkm_vmm_node_insert(vmm, tmp);
--
2.25.1
