[UR] Fix usm pools creation failure at context initialization

sycl/source/detail/device_impl.cpp

@@ -283,7 +283,7 @@ std::vector<device> device_impl::create_sub_devices(
                               affinityDomainToString(AffinityDomain) + ".");
   }
 
-  ur_device_partition_property_t Prop;
+  ur_device_partition_property_t Prop{};
   Prop.type = UR_DEVICE_PARTITION_BY_AFFINITY_DOMAIN;
   Prop.value.affinity_domain =
       static_cast<ur_device_affinity_domain_flags_t>(AffinityDomain);
@@ -310,9 +310,8 @@ std::vector<device> device_impl::create_sub_devices() const {
         "sycl::info::partition_property::ext_intel_partition_by_cslice.");
   }
 
-  ur_device_partition_property_t Prop;
+  ur_device_partition_property_t Prop{};
   Prop.type = UR_DEVICE_PARTITION_BY_CSLICE;
-
   ur_device_partition_properties_t Properties{};
   Properties.stype = UR_STRUCTURE_TYPE_DEVICE_PARTITION_PROPERTIES;
   Properties.pProperties = &Prop;

sycl/test-e2e/Adapters/level_zero/context_create_sub_sub_device.cpp

@@ -0,0 +1,41 @@
+// REQUIRES:  arch-intel_gpu_pvc, level_zero
+// UNSUPPORTED: gpu-intel-pvc-1T
+
+// DEFINE: %{setup_env} = env ZE_FLAT_DEVICE_HIERARCHY=COMPOSITE ZE_AFFINITY_MASK=0 ZEX_NUMBER_OF_CCS=0:4
+// RUN: %{build} -o %t.out
+// RUN: %{setup_env} %{run} %t.out
+
+// Check that context can be created successfully when sub-sub-devices are
+// exposed.
+#include <iostream>
+#include <sycl/detail/core.hpp>
+#include <vector>
+
+using namespace sycl;
+
+int main() {
+  std::cout << "[info] start context_create_sub_sub_device test" << std::endl;
+  device d;
+  std::vector<device> subsubdevices;
+
+  auto subdevices = d.create_sub_devices<
+      info::partition_property::partition_by_affinity_domain>(
+      info::partition_affinity_domain::next_partitionable);
+  std::cout << "[info] sub device size = " << subdevices.size() << std::endl;
+
+  for (auto &subdev : subdevices) {
+    subsubdevices = subdev.create_sub_devices<
+        info::partition_property::ext_intel_partition_by_cslice>();
+
+    std::cout << "[info] sub-sub device size = " << subsubdevices.size()
+              << std::endl;
+  }
+
+  // Create contexts
+  context ctx1(d);
+  context ctx2(subdevices);
+  context ctx3(subsubdevices);
+
+  std::cout << "[info] contexts created successfully" << std::endl;
+  return 0;
+}

unified-runtime/source/adapters/level_zero/device.hpp

@@ -248,16 +248,20 @@ struct ur_device_handle_t_ : ur_object {
   ur::RefCount RefCount;
 };
 
-inline std::vector<ur_device_handle_t>
-CollectDevicesAndSubDevices(const std::vector<ur_device_handle_t> &Devices) {
+// Collects a flat vector of unique devices for USM memory pool creation.
+// Traverses the input devices and their sub-devices, ensuring each Level Zero
+// device handle appears only once in the result.
+inline std::vector<ur_device_handle_t> CollectDevicesForUsmPoolCreation(
+    const std::vector<ur_device_handle_t> &Devices) {
   std::vector<ur_device_handle_t> DevicesAndSubDevices;
-  std::unordered_set<ur_device_handle_t> Seen;
+  std::unordered_set<ze_device_handle_t> Seen;
+
   std::function<void(const std::vector<ur_device_handle_t> &)>
       CollectDevicesAndSubDevicesRec =
           [&](const std::vector<ur_device_handle_t> &Devices) {
             for (auto &Device : Devices) {
-              // Only add device if has not been seen before.
-              if (Seen.insert(Device).second) {
+              // Only add device if ZeDevice has not been seen before.
+              if (Seen.insert(Device->ZeDevice).second) {
                 DevicesAndSubDevices.push_back(Device);
                 CollectDevicesAndSubDevicesRec(Device->SubDevices);
               }

unified-runtime/source/adapters/level_zero/usm.cpp

@@ -1056,7 +1056,8 @@ ur_usm_pool_handle_t_::ur_usm_pool_handle_t_(ur_context_handle_t Context,
     }
   }
 
-  auto DevicesAndSubDevices = CollectDevicesAndSubDevices(Context->Devices);
+  auto DevicesAndSubDevices =
+      CollectDevicesForUsmPoolCreation(Context->Devices);
   auto Descriptors = usm::pool_descriptor::createFromDevices(
       this, Context, DevicesAndSubDevices);
   for (auto &Desc : Descriptors) {

unified-runtime/source/adapters/level_zero/v2/usm.cpp

@@ -168,7 +168,7 @@ ur_usm_pool_handle_t_::ur_usm_pool_handle_t_(ur_context_handle_t hContext,
   }
 
   auto devicesAndSubDevices =
-      CollectDevicesAndSubDevices(hContext->getDevices());
+      CollectDevicesForUsmPoolCreation(hContext->getDevices());
   auto descriptors = usm::pool_descriptor::createFromDevices(
       this, hContext, devicesAndSubDevices);
   for (auto &desc : descriptors) {