eBay · shosseinimotlagh · Oct 1, 2026 · Sep 17, 2026 · Sep 17, 2026 · Sep 17, 2026
diff --git a/conanfile.py b/conanfile.py
@@ -2,7 +2,7 @@
 
 class HomestoreConan(ConanFile):
     name = "homestore"
-    version = "3.8.7"
+    version = "3.8.8"
 
     homepage = "https://github.corp.ebay.com/SDS/homestore"
     description = "HomeStore"
@@ -55,16 +55,17 @@ def build_requirements(self):
         self.test_requires("gtest/1.15.0")
 
     def requirements(self):
-        self.requires("iomgr/8.8.4")
-        self.requires("sisl/8.9.6")
+        self.requires("iomgr/8.8.7")
+        self.requires("sisl/8.9.8")
 
         # FOSS, rarely updated
         self.requires("boost/1.79.0")
         self.requires("farmhash/cci.20190513@")
         self.requires("folly/2022.01.31.00")
         self.requires("isa-l/2.30.0")
-        self.requires("nlohmann_json/3.12.0")
+        self.requires("nlohmann_json/[^3.11]")
         self.requires("spdk/nbi.21.07.y")
+        self.requires("openssl/1.1.1w", override=True)
 
     def build(self):
         cmake = CMake(self)

diff --git a/locks/base.lock b/locks/base.lock
@@ -2,7 +2,7 @@
  "graph_lock": {
   "nodes": {
    "0": {
-    "ref": "homestore/3.8.7",
+    "ref": "homestore/3.8.8",
     "requires": [
      "1",
      "2",
@@ -21,7 +21,7 @@
     "context": "host"
    },
    "1": {
-    "ref": "iomgr/8.8.4#8b6efbb0f5a6dbfa21d54d333d4c85f7",
+    "ref": "iomgr/8.8.7#a8b556d68402d7704b82287b1a8c9b72",
     "requires": [
      "2",
      "3",
@@ -37,7 +37,7 @@
     "context": "host"
    },
    "2": {
-    "ref": "sisl/8.9.6#8ad5a667b06c1a75d1f8efab55a840ce",
+    "ref": "sisl/8.9.8#85065452eb527275f3a889e2918d4881",
     "requires": [
      "3",
      "7",
@@ -70,11 +70,11 @@
     "context": "host"
    },
    "5": {
-    "ref": "bzip2/1.0.8#411fc05e80d47a89045edc1ee6f23c1d",
+    "ref": "bzip2/1.0.8#8779e3ee0cf27649212cd3fc0db4438b",
     "context": "host"
    },
    "6": {
-    "ref": "libbacktrace/cci.20210118#ec1aa63bbc10145c6a299e68e711670c",
+    "ref": "libbacktrace/cci.20210118#f5d18dee9942ec36058b965afa867e7b",
     "context": "host"
    },
    "7": {
@@ -105,10 +105,7 @@
     "context": "host"
    },
    "11": {
-    "ref": "openssl/3.6.0#89e8af1d4a21afcac0557079d23d8890",
-    "requires": [
-     "4"
-    ],
+    "ref": "openssl/1.1.1w#c5ede42cc8ea41086b99aa237ad138d2",
     "context": "host"
    },
    "12": {
@@ -143,11 +140,11 @@
     "context": "host"
    },
    "15": {
-    "ref": "double-conversion/3.2.0#dba4f6ac0cfbfb3ab6f0b6bd4130af55",
+    "ref": "double-conversion/3.2.0#640e35791a4bac95b0545e2f54b7aceb",
     "context": "host"
    },
    "16": {
-    "ref": "gflags/2.2.2#48d1262ffac8d30c3224befb8275a533",
+    "ref": "gflags/2.2.2#b15c28c567c7ade7449cf994168a559f",
     "context": "host"
    },
    "17": {
@@ -167,7 +164,7 @@
     "context": "host"
    },
    "19": {
-    "ref": "xz_utils/5.2.5#774a53815bc66047a56ef8470a144a91",
+    "ref": "xz_utils/5.2.5#a6d90890193dc851fa0d470163271c7a",
     "context": "host"
    },
    "20": {
@@ -202,11 +199,11 @@
     "context": "host"
    },
    "26": {
-    "ref": "libsodium/1.0.18#9e310e52ed60084484c5f640ab88883a",
+    "ref": "libsodium/1.0.18#7429a9e5351cc67bea3537229921714d",
     "context": "host"
    },
    "27": {
-    "ref": "libiberty/9.1.0#a6a0b042484db9cefa233a8aa31a33c5",
+    "ref": "libiberty/9.1.0#3060045a116b0fff6d4937b0fc9cfc0e",
     "context": "host"
    },
    "28": {

diff --git a/locks/debug_deps.lock b/locks/debug_deps.lock
diff --git a/locks/release_deps.lock b/locks/release_deps.lock
diff --git a/locks/sanitize_deps.lock b/locks/sanitize_deps.lock
diff --git a/src/api/blob_view.hpp b/src/api/blob_view.hpp
@@ -0,0 +1,36 @@
+/*********************************************************************************
+ * Modifications Copyright 2017-2019 eBay Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *    https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed
+ * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+ * CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ *********************************************************************************/
+#pragma once
+
+/* NOTE: This file must stay dependency-free (only <memory> and sisl::blob) so it can be
+ * included both from public interface headers (e.g. vol_interface.hpp, which must avoid
+ * including homestore-internal headers) and from internal engine headers.
+ */
+
+#include <memory>
+
+#include <sisl/fds/buffer.hpp>
+
+namespace homestore {
+
+/* A sisl::blob that also carries a type-erased ownership token. As long as a blob_view
+ * instance is alive, m_holder keeps whatever backing memory blob.bytes points into alive too
+ * (whatever that memory actually is is opaque here on purpose). Callers should bind the
+ * result of an at_offset()-style accessor to `auto` so this token is not sliced away. */
+struct blob_view : public sisl::blob {
+    std::shared_ptr< void > m_holder;
+};
+
+} // namespace homestore
diff --git a/src/api/vol_interface.hpp b/src/api/vol_interface.hpp
@@ -48,6 +48,8 @@
 #include <engine/common/homestore_header.hpp>
 #include <engine/device/device.h>
 
+#include "blob_view.hpp"
+
 namespace homestore {
 class Volume;
 class Snapshot;
@@ -319,7 +321,7 @@ class VolInterface {
     virtual std::map< boost::uuids::uuid, uint64_t > get_used_size(const VolumePtr& vol) = 0;
     virtual uint64_t get_page_size(const VolumePtr& vol) = 0;
     virtual boost::uuids::uuid get_uuid(std::shared_ptr< Volume > vol) = 0;
-    virtual sisl::blob at_offset(const boost::intrusive_ptr< BlkBuffer >& buf, uint32_t offset) = 0;
+    virtual blob_view at_offset(const boost::intrusive_ptr< BlkBuffer >& buf, uint32_t offset) = 0;
     virtual VolumePtr create_volume(const vol_params& params) = 0;
     virtual std::error_condition remove_volume(const boost::uuids::uuid& uuid,
                                                const hs_comp_callback& shutdown_done_cb = nullptr) = 0;

diff --git a/src/engine/blkstore/blkstore.hpp b/src/engine/blkstore/blkstore.hpp
@@ -116,7 +116,7 @@ struct blkstore_req : public virtualdev_req {
         }
     };
 
-    static auto to_blkstore_req(auto& req) { return boost::static_pointer_cast< blkstore_req< Buffer > >(req); }
+    static auto to_blkstore_req(auto& req) { return boost::dynamic_pointer_cast< blkstore_req< Buffer > >(req); }
 
     static boost::intrusive_ptr< blkstore_req< Buffer > > make_request() {
         return boost::intrusive_ptr< blkstore_req< Buffer > >(

diff --git a/src/engine/cache/cache.h b/src/engine/cache/cache.h
@@ -23,6 +23,7 @@
 #include <limits>
 #include <memory>
 #include <mutex>
+#include <folly/SharedMutex.h>
 #include <sstream>
 #include <string>
 #include <type_traits>
@@ -36,6 +37,7 @@
 #include <sisl/utility/enum.hpp>
 #include <sisl/utility/obj_life_counter.hpp>
 
+#include "api/blob_view.hpp"
 #include "engine/common/homestore_assert.hpp"
 #include "engine/common/homestore_config.hpp"
 #include "engine/homeds/hash/intrusive_hashset.hpp"
@@ -45,6 +47,12 @@
 
 SISL_LOGGING_DECL(cache, cache_vmod_evict, cache_vmod_read, cache_vmod_write)
 
+#ifdef _PRERELEASE
+#include <chrono>
+#include <thread>
+#include "engine/common/homestore_flip.hpp"
+#endif
+
 namespace homestore {
 
 #define CurrentEvictor LRUEvictor
@@ -208,6 +216,7 @@ class CacheBuffer : public CacheRecord {
     bool recovered;
 #endif
     K m_key;                                         // Key to access this cache
+    mutable folly::SharedMutexReadPriority m_mem_mtx; // protects m_mem and m_data_offset (4 bytes vs 56 for std::shared_mutex)
     boost::intrusive_ptr< homeds::MemVector > m_mem; // Memory address which is what this buffer contained with
     sisl::atomic_counter< uint32_t > m_refcount;     // Refcount
     uint32_t m_data_offset;                          // offset in m_mem that it points to
@@ -302,18 +311,41 @@ class CacheBuffer : public CacheRecord {
     uint32_t get_data_offset() const { return m_data_offset; }
 
     bool update_missing_piece(const uint32_t offset, const uint32_t size, uint8_t* const ptr) {
-        const bool inserted{get_memvec().update_missing_piece(m_data_offset + offset, size, ptr, [this]() { init(); })};
+        boost::intrusive_ptr< homeds::MemVector > mv;
+        uint32_t data_offset;
+        {
+            std::shared_lock< folly::SharedMutexReadPriority > lk{m_mem_mtx};
+            mv = m_mem;
+            data_offset = m_data_offset;
+        }
+#ifdef _PRERELEASE
+        if (homestore_flip->test_flip("cache_buf_update_before_use")) {
+            std::this_thread::sleep_for(std::chrono::microseconds(1));
+        }
+#endif
+        const bool inserted{mv->update_missing_piece(data_offset + offset, size, ptr, [this]() { init(); })};
         return inserted;
     }
 
     uint32_t insert_missing_pieces(const uint32_t offset, const uint32_t size_to_read,
                                    std::vector< std::pair< uint32_t, uint32_t > >& missing_mp) {
-        const uint32_t inserted_size{
-            get_memvec().insert_missing_pieces(m_data_offset + offset, size_to_read, missing_mp)};
+        boost::intrusive_ptr< homeds::MemVector > mv;
+        uint32_t data_offset;
+        {
+            std::shared_lock< folly::SharedMutexReadPriority > lk{m_mem_mtx};
+            mv = m_mem;
+            data_offset = m_data_offset;
+        }
+#ifdef _PRERELEASE
+        if (homestore_flip->test_flip("wb_cache_get_memvec_before_use")) {
+            std::this_thread::sleep_for(std::chrono::microseconds(100));
+        }
+#endif
+        const uint32_t inserted_size{mv->insert_missing_pieces(data_offset + offset, size_to_read, missing_mp)};
         /* it should return a relative offset */
-        for (auto& missing_mp : missing_mp) {
-            assert(missing_mp.first >= m_data_offset);
-            missing_mp.first -= m_data_offset;
+        for (auto& mp : missing_mp) {
+            assert(mp.first >= data_offset);
+            mp.first -= data_offset;
         }
 
         return inserted_size;
@@ -325,6 +357,7 @@ class CacheBuffer : public CacheRecord {
 
     void set_memvec(boost::intrusive_ptr< homeds::MemVector > vec, const uint32_t offset, const uint32_t size) {
         HS_DBG_ASSERT_LE(size, UINT16_MAX);
+        std::unique_lock< folly::SharedMutexReadPriority > lk{m_mem_mtx};
         m_mem = std::move(vec);
         m_data_offset = offset;
         m_cache_size = size;
@@ -352,11 +385,21 @@ class CacheBuffer : public CacheRecord {
         return m_mem;
     }
 
-    sisl::blob at_offset(const uint32_t offset) const {
-        sisl::blob b;
+    blob_view at_offset(const uint32_t offset) const {
+        boost::intrusive_ptr< homeds::MemVector > mv;
+        uint32_t data_offset;
+        {
+            std::shared_lock< folly::SharedMutexReadPriority > lk{m_mem_mtx};
+            mv = m_mem;
+            data_offset = m_data_offset;
+        }
+        blob_view b;
         b.bytes = nullptr;
         b.size = 0;
-        get_memvec().get(&b, m_data_offset + offset);
+        mv->get(&b, data_offset + offset);
+        // keep MemVector alive for as long as the caller holds this blob_view, not just
+        // for the duration of this accessor call (see api/blob_view.hpp)
+        b.m_holder = std::make_shared< boost::intrusive_ptr< homeds::MemVector > >(std::move(mv));
         return b;
     }
 

diff --git a/src/engine/homeds/CMakeLists.txt b/src/engine/homeds/CMakeLists.txt
@@ -34,6 +34,15 @@ if (${non_io_tests})
     target_sources(test_btree_crud PRIVATE tests/test_btree_crud.cpp)
     target_link_libraries(test_btree_crud homestore ${COMMON_TEST_DEPS})
 
+    add_executable(test_wb_cache_race)
+    target_sources(test_wb_cache_race PRIVATE tests/test_wb_cache_race.cpp)
+    target_link_libraries(test_wb_cache_race homestore ${COMMON_TEST_DEPS})
+    # SIMULATE_WB_MEM_RACE=ON: activates the unfixed wb_req->m_mem code path (no mutex) for Race B reproduction.
+    option(SIMULATE_WB_MEM_RACE "Activate unfixed wb_req->m_mem path (no mutex) for Race B reproduction" OFF)
+    if(SIMULATE_WB_MEM_RACE)
+        target_compile_definitions(test_wb_cache_race PRIVATE SIMULATE_WB_MEM_RACE)
+    endif()
+
     add_executable(test_hash)
     target_sources(test_hash PRIVATE tests/test_hashset.cpp)
     target_link_libraries(test_hash ${COMMON_TEST_DEPS} benchmark::benchmark)
@@ -50,6 +59,10 @@ if (${non_io_tests})
     target_compile_options(test_load PRIVATE -Wno-deprecated)
     target_link_libraries(test_load homeblks ${COMMON_TEST_DEPS})
 
+    add_executable(test_wb_cache_integration)
+    target_sources(test_wb_cache_integration PRIVATE tests/test_wb_cache_integration.cpp)
+    target_link_libraries(test_wb_cache_integration homeblks ${COMMON_TEST_DEPS})
+
     add_executable(test_iomgr_exec)
     target_sources(test_iomgr_exec PRIVATE
           tests/test_iomgr_executor.cpp
@@ -62,6 +75,8 @@ if (${non_io_tests})
         target_sources(test_threadpool PRIVATE tests/test_thread_pool.cpp)
         target_link_libraries(test_threadpool ${COMMON_TEST_DEPS})
     endif()
+    add_test(NAME WbCacheRace COMMAND ${CMAKE_SOURCE_DIR}/test_wrap.sh ${CMAKE_BINARY_DIR}/bin/test_wb_cache_race)
+    add_test(NAME WbCacheIntegration COMMAND ${CMAKE_SOURCE_DIR}/test_wrap.sh ${CMAKE_BINARY_DIR}/bin/test_wb_cache_integration)
     add_test(NAME BTreeCRUD COMMAND ${CMAKE_SOURCE_DIR}/test_wrap.sh ${CMAKE_BINARY_DIR}/bin/test_btree_crud)
     add_test(NAME Hash COMMAND ${CMAKE_SOURCE_DIR}/test_wrap.sh ${CMAKE_BINARY_DIR}/bin/test_hash)
     add_test(NAME Avector COMMAND ${CMAKE_SOURCE_DIR}/test_wrap.sh ${CMAKE_BINARY_DIR}/bin/test_avector)

diff --git a/src/engine/homeds/btree/ssd_btree.hpp b/src/engine/homeds/btree/ssd_btree.hpp
@@ -252,7 +252,7 @@ class SSDBtreeStore {
 
     static uint8_t* get_physical(const SSDBtreeNode* const bn) {
         const wb_cache_buffer_t* const bbuf{static_cast< const wb_cache_buffer_t* >(bn)};
-        const sisl::blob b{bbuf->at_offset(0)};
+        const auto b{bbuf->at_offset(0)};
         return b.bytes;
     }
 
@@ -290,7 +290,7 @@ class SSDBtreeStore {
     _init_node(SSDBtreeStore* store, auto& safe_buf, bool is_leaf, const BlkId& blkid,
                const boost::intrusive_ptr< SSDBtreeNode >& copy_from = nullptr) {
         // Access the physical node buffer and initialize it
-        sisl::blob b = safe_buf->at_offset(0);
+        auto b = safe_buf->at_offset(0);
         HS_DBG_ASSERT_EQ(b.size, store->get_node_size());
         if (is_leaf) {
             bnodeid_t bid = blkid.to_integer();

diff --git a/src/engine/homeds/btree/writeBack_cache.hpp b/src/engine/homeds/btree/writeBack_cache.hpp
@@ -427,6 +427,11 @@ class WriteBackCache : public std::enable_shared_from_this< WriteBackCache< K, V
         auto shared_this = this->shared_from_this();
         queue_flush_buffers([shared_this, cp_id, it = m_req_list[cp_id]->begin(true /* latest */),
                              bt_cp_id = bcp->cp_id, cbq_id = s_cbq_id]() mutable -> bool {
+#ifdef _PRERELEASE
+            if (homestore_flip->test_flip("wb_flush_delay_before_write")) {
+                std::this_thread::sleep_for(std::chrono::milliseconds(200));
+            }
+#endif
             size_t write_count{0};
             size_t dep_wait_count{0};