[Mesa-dev] [PATCH 3/3] anv/pipeline: Don't dereference NULL dynamic state pointers

[Nanley Chery]

From: Nanley Chery <nanley.g.chery at intel.com>

Add guards to prevent dereferencing NULL dynamic pipeline state.

This fixes a segfault seen in the McNopper demo, VKTS_Example09.

Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
Cc: "12.0" <mesa-stable at lists.freedesktop.org>
---
 src/intel/vulkan/anv_pipeline.c | 51 ++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/src/intel/vulkan/anv_pipeline.c b/src/intel/vulkan/anv_pipeline.c
index d5a3a21..4ce13eb 100644
--- a/src/intel/vulkan/anv_pipeline.c
+++ b/src/intel/vulkan/anv_pipeline.c
@@ -979,11 +979,28 @@ copy_non_dynamic_state(struct anv_pipeline *pipeline,
 
    struct anv_dynamic_state *dynamic = &pipeline->dynamic_state;
 
-   dynamic->viewport.count = pCreateInfo->pViewportState->viewportCount;
-   if (states & (1 << VK_DYNAMIC_STATE_VIEWPORT)) {
-      typed_memcpy(dynamic->viewport.viewports,
-                   pCreateInfo->pViewportState->pViewports,
-                   pCreateInfo->pViewportState->viewportCount);
+   bool fs_used = pipeline->active_stages & VK_SHADER_STAGE_FRAGMENT_BIT;
+   bool color_att_used = false;
+   for (unsigned i = 0; i < subpass->color_count; ++i) {
+      if (subpass->color_attachments[i] != VK_ATTACHMENT_UNUSED) {
+         color_att_used = true;
+         break;
+      }
+   }
+
+   /* Section 9.2 of the Vulkan 1.0.15 spec says:
+    *
+    *    pViewportState is [...] NULL if the pipeline
+    *    has rasterization disabled.
+    */
+   if (fs_used) {
+      assert(pCreateInfo->pViewportState);
+      dynamic->viewport.count = pCreateInfo->pViewportState->viewportCount;
+      if (states & (1 << VK_DYNAMIC_STATE_VIEWPORT)) {
+         typed_memcpy(dynamic->viewport.viewports,
+                     pCreateInfo->pViewportState->pViewports,
+                     pCreateInfo->pViewportState->viewportCount);
+      }
    }
 
    dynamic->scissor.count = pCreateInfo->pViewportState->scissorCount;
@@ -1008,7 +1025,14 @@ copy_non_dynamic_state(struct anv_pipeline *pipeline,
          pCreateInfo->pRasterizationState->depthBiasSlopeFactor;
    }
 
-   if (states & (1 << VK_DYNAMIC_STATE_BLEND_CONSTANTS)) {
+   /* Section 9.2 of the Vulkan 1.0.15 spec says:
+    *
+    *    pColorBlendState is [...] NULL if the pipeline has rasterization
+    *    disabled or if the subpass of the render pass the pipeline is
+    *    created against does not use any color attachments.
+    */
+   if (fs_used && color_att_used &&
+       states & (1 << VK_DYNAMIC_STATE_BLEND_CONSTANTS)) {
       assert(pCreateInfo->pColorBlendState);
       typed_memcpy(dynamic->blend_constants,
                    pCreateInfo->pColorBlendState->blendConstants, 4);
@@ -1020,14 +1044,16 @@ copy_non_dynamic_state(struct anv_pipeline *pipeline,
     * no need to override the depthstencil defaults in
     * anv_pipeline::dynamic_state when there is no depthstencil attachment.
     *
-    * From the Vulkan spec (20 Oct 2015, git-aa308cb):
+    * Section 9.2 of the Vulkan 1.0.15 spec says:
     *
-    *    pDepthStencilState [...] may only be NULL if renderPass and subpass
-    *    specify a subpass that has no depth/stencil attachment.
+    *    pDepthStencilState is [...] NULL if the pipeline has rasterization
+    *    disabled or if the subpass of the render pass the pipeline is created
+    *    against does not use a depth/stencil attachment.
     */
-   if (subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED) {
+   if (fs_used && subpass->depth_stencil_attachment != VK_ATTACHMENT_UNUSED) {
+      assert(pCreateInfo->pDepthStencilState);
+
       if (states & (1 << VK_DYNAMIC_STATE_DEPTH_BOUNDS)) {
-         assert(pCreateInfo->pDepthStencilState);
          dynamic->depth_bounds.min =
             pCreateInfo->pDepthStencilState->minDepthBounds;
          dynamic->depth_bounds.max =
@@ -1035,7 +1061,6 @@ copy_non_dynamic_state(struct anv_pipeline *pipeline,
       }
 
       if (states & (1 << VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK)) {
-         assert(pCreateInfo->pDepthStencilState);
          dynamic->stencil_compare_mask.front =
             pCreateInfo->pDepthStencilState->front.compareMask;
          dynamic->stencil_compare_mask.back =
@@ -1043,7 +1068,6 @@ copy_non_dynamic_state(struct anv_pipeline *pipeline,
       }
 
       if (states & (1 << VK_DYNAMIC_STATE_STENCIL_WRITE_MASK)) {
-         assert(pCreateInfo->pDepthStencilState);
          dynamic->stencil_write_mask.front =
             pCreateInfo->pDepthStencilState->front.writeMask;
          dynamic->stencil_write_mask.back =
@@ -1051,7 +1075,6 @@ copy_non_dynamic_state(struct anv_pipeline *pipeline,
       }
 
       if (states & (1 << VK_DYNAMIC_STATE_STENCIL_REFERENCE)) {
-         assert(pCreateInfo->pDepthStencilState);
          dynamic->stencil_reference.front =
             pCreateInfo->pDepthStencilState->front.reference;
          dynamic->stencil_reference.back =
-- 
2.8.3