drm/radeon: fix regression in UMS CS ioctl

radeon_cs_parser_init is called by both the legacy UMS
CS ioctl and the KMS CS ioctl.  Protect KMS specific
pieces of the code by checking that rdev is not NULL.

Reported-by: Michael Burian <michael.burian@sbg.at>

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 17 insertions, 14 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index 0137689ed461..142f89462aa4 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -147,6 +147,7 @@ static int radeon_cs_sync_rings(struct radeon_cs_parser *p)
                                            sync_to_ring, p->ring);
 }
 
+/* XXX: note that this is called from the legacy UMS CS ioctl as well */
 int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
 {
         struct drm_radeon_cs *cs = data;
@@ -245,22 +246,24 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
                 }
         }
 
-        if ((p->cs_flags & RADEON_CS_USE_VM) &&
-            !p->rdev->vm_manager.enabled) {
-                DRM_ERROR("VM not active on asic!\n");
-                return -EINVAL;
-        }
-
-        /* we only support VM on SI+ */
-        if ((p->rdev->family >= CHIP_TAHITI) &&
-            ((p->cs_flags & RADEON_CS_USE_VM) == 0)) {
-                DRM_ERROR("VM required on SI+!\n");
-                return -EINVAL;
-        }
+        /* these are KMS only */
+        if (p->rdev) {
+                if ((p->cs_flags & RADEON_CS_USE_VM) &&
+                    !p->rdev->vm_manager.enabled) {
+                        DRM_ERROR("VM not active on asic!\n");
+                        return -EINVAL;
+                }
 
-        if (radeon_cs_get_ring(p, ring, priority))
-                return -EINVAL;
+                /* we only support VM on SI+ */
+                if ((p->rdev->family >= CHIP_TAHITI) &&
+                    ((p->cs_flags & RADEON_CS_USE_VM) == 0)) {
+                        DRM_ERROR("VM required on SI+!\n");
+                        return -EINVAL;
+                }
 
+                if (radeon_cs_get_ring(p, ring, priority))
+                        return -EINVAL;
+        }
 
         /* deal with non-vm */
         if ((p->chunk_ib_idx != -1) &&