<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Jul 13, 2016 at 3:34 PM, Nanley Chery <span dir="ltr"><<a href="mailto:nanleychery@gmail.com" target="_blank">nanleychery@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Section 13.2.3. of the Vulkan spec requires that implementations be able to<br>
bind sparsely-defined Descriptor Sets without any errors or exceptions.<br>
<br>
When binding a descriptor set that contains a dynamic buffer binding/descriptor,<br>
the driver attempts to dereference the descriptor's buffer_view field if it is<br>
non-NULL. It currently segfaults on undefined descriptors as this field is never<br>
zero-initialized. Zero undefined descriptors to avoid segfaulting. This<br>
solution was suggested by Jason Ekstrand.<br>
<br>
Bugzilla: <a href="https://bugs.freedesktop.org/show_bug.cgi?id=96850" rel="noreferrer" target="_blank">https://bugs.freedesktop.org/show_bug.cgi?id=96850</a><br>
Cc: 12.0 <<a href="mailto:mesa-stable@lists.freedesktop.org">mesa-stable@lists.freedesktop.org</a>><br>
Signed-off-by: Nanley Chery <<a href="mailto:nanley.g.chery@intel.com">nanley.g.chery@intel.com</a>><br>
---<br>
src/intel/vulkan/anv_descriptor_set.c | 9 +++++++--<br>
1 file changed, 7 insertions(+), 2 deletions(-)<br>
<br>
diff --git a/src/intel/vulkan/anv_descriptor_set.c b/src/intel/vulkan/anv_descriptor_set.c<br>
index 448ae0e..f06d2e4 100644<br>
--- a/src/intel/vulkan/anv_descriptor_set.c<br>
+++ b/src/intel/vulkan/anv_descriptor_set.c<br>
@@ -412,8 +412,8 @@ anv_descriptor_set_create(struct anv_device *device,<br>
/* Go through and fill out immutable samplers if we have any */<br>
struct anv_descriptor *desc = set->descriptors;<br>
for (uint32_t b = 0; b < layout->binding_count; b++) {<br>
- if (layout->binding[b].immutable_samplers) {<br>
- for (uint32_t i = 0; i < layout->binding[b].array_size; i++) {<br>
+ for (uint32_t i = 0; i < layout->binding[b].array_size; i++) {<br>
+ if (layout->binding[b].immutable_samplers) {<br>
/* The type will get changed to COMBINED_IMAGE_SAMPLER in<br>
* UpdateDescriptorSets if needed. However, if the descriptor<br>
* set has an immutable sampler, UpdateDescriptorSets may never<br>
@@ -423,6 +423,11 @@ anv_descriptor_set_create(struct anv_device *device,<br>
.type = VK_DESCRIPTOR_TYPE_SAMPLER,<br>
.sampler = layout->binding[b].immutable_samplers[i],<br>
};<br>
+ } else {<br>
+ /* By defining the descriptors to be zero now, we can later verify that<br>
+ * the descriptor has not been populated with user data.<br>
+ */<br>
+ zero(desc[i]);<br></blockquote><div><br></div><div>I think I'd rather just zero the whole thing rather than one descriptor at a time. Given that the memset will use vectorized memory operations, it's almost certainly just as fast if not faster to do so and I think it's more clear.<br><br></div><div>--Jason<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
}<br>
}<br>
desc += layout->binding[b].array_size;<br>
<span class="HOEnZb"><font color="#888888">--<br>
2.9.0<br>
<br>
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