drm/i915: Call i915_perf_fini() on init_hw error unwind

We have to cleanup after i915_perf_init(), even on the error path, as it
passes a pointer into the module to the sysfs core. If we fail to
unregister the sysctl table, we leave a dangling pointer which then may
explode anytime later.

Fixes: 9f9b2792b6d3 ("drm/i915/perf: reuse timestamp frequency from device info")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180414091233.32224-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.c

@@ -1101,30 +1101,32 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
 
 	ret = i915_ggtt_probe_hw(dev_priv);
 	if (ret)
-		return ret;
+		goto err_perf;
 
-	/* WARNING: Apparently we must kick fbdev drivers before vgacon,
-	 * otherwise the vga fbdev driver falls over. */
+	/*
+	 * WARNING: Apparently we must kick fbdev drivers before vgacon,
+	 * otherwise the vga fbdev driver falls over.
+	 */
 	ret = i915_kick_out_firmware_fb(dev_priv);
 	if (ret) {
 		DRM_ERROR("failed to remove conflicting framebuffer drivers\n");
-		goto out_ggtt;
+		goto err_ggtt;
 	}
 
 	ret = i915_kick_out_vgacon(dev_priv);
 	if (ret) {
 		DRM_ERROR("failed to remove conflicting VGA console\n");
-		goto out_ggtt;
+		goto err_ggtt;
 	}
 
 	ret = i915_ggtt_init_hw(dev_priv);
 	if (ret)
-		return ret;
+		goto err_ggtt;
 
 	ret = i915_ggtt_enable_hw(dev_priv);
 	if (ret) {
 		DRM_ERROR("failed to enable GGTT\n");
-		goto out_ggtt;
+		goto err_ggtt;
 	}
 
 	pci_set_master(pdev);
@@ -1135,7 +1137,7 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
 		if (ret) {
 			DRM_ERROR("failed to set DMA mask\n");
 
-			goto out_ggtt;
+			goto err_ggtt;
 		}
 	}
 
@@ -1153,7 +1155,7 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
 		if (ret) {
 			DRM_ERROR("failed to set DMA mask\n");
 
-			goto out_ggtt;
+			goto err_ggtt;
 		}
 	}
 
@@ -1186,13 +1188,14 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
 
 	ret = intel_gvt_init(dev_priv);
 	if (ret)
-		goto out_ggtt;
+		goto err_ggtt;
 
 	return 0;
 
-out_ggtt:
+err_ggtt:
 	i915_ggtt_cleanup_hw(dev_priv);
-
+err_perf:
+	i915_perf_fini(dev_priv);
 	return ret;
 }