From: Jon Derrick <jonathan.derrick@intel.com>
Date: Sat, 16 Mar 2019 00:05:18 +0000 (-0600)
Subject: drm/nouveau/mmu: qualify vmm during dtor
X-Git-Tag: v4.19.98~13
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7b88ac504746972c6a0ad99d017311f4a4251ab0;p=thirdparty%2Fkernel%2Fstable.git

drm/nouveau/mmu: qualify vmm during dtor

commit 15516bf9abaa41421a6ded79a5a2fee86f9594e5 upstream.

If the BAR initialization failed it may leave the vmm structure in an
unitialized state, leading to a null-pointer-dereference when the vmm is
dereferenced during teardown.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Sushma Kalakota <sushmax.kalakota@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
index 7459def78d504..5f8b8b399b97b 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
@@ -1423,7 +1423,7 @@ nvkm_vmm_get(struct nvkm_vmm *vmm, u8 page, u64 size, struct nvkm_vma **pvma)
 void
 nvkm_vmm_part(struct nvkm_vmm *vmm, struct nvkm_memory *inst)
 {
-	if (inst && vmm->func->part) {
+	if (inst && vmm && vmm->func->part) {
 		mutex_lock(&vmm->mutex);
 		vmm->func->part(vmm, inst);
 		mutex_unlock(&vmm->mutex);