linux-kernel - [PATCH AUTOSEL 4.18 31/65] drm/nouveau/mmu: don't attempt to dereference vmm without valid instance pointer

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Message-ID: <20181001003754.146961-31-alexander.levin@microsoft.com>
Date:   Mon, 1 Oct 2018 00:38:21 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Ben Skeggs <bskeggs@...hat.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 31/65] drm/nouveau/mmu: don't attempt to
 dereference vmm without valid instance pointer

From: Ben Skeggs <bskeggs@...hat.com>

[ Upstream commit 51ed833c881b9d96557c773f6a37018d79e29a46 ]

Fixes oopses in certain failure paths.

Signed-off-by: Ben Skeggs <bskeggs@...hat.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
index de269eb482dd..7459def78d50 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 (vmm->func->part && inst) {
+	if (inst && vmm->func->part) {
 		mutex_lock(&vmm->mutex);
 		vmm->func->part(vmm, inst);
 		mutex_unlock(&vmm->mutex);
-- 
2.17.1