Add PoolResource fuzzer

Fuzzes PoolResource with random allocations/deallocations, and multiple
asserts.

Co-Authored-By: Pieter Wuille <pieter@wuille.net>

src/Makefile.test.include

@@ -301,6 +301,7 @@ test_fuzz_fuzz_SOURCES = \
  test/fuzz/partially_downloaded_block.cpp \
  test/fuzz/policy_estimator.cpp \
  test/fuzz/policy_estimator_io.cpp \
+ test/fuzz/poolresource.cpp \
  test/fuzz/pow.cpp \
  test/fuzz/prevector.cpp \
  test/fuzz/primitives_transaction.cpp \

src/test/fuzz/poolresource.cpp

@@ -0,0 +1,174 @@
+// Copyright (c) 2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <span.h>
+#include <support/allocators/pool.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+#include <test/util/poolresourcetester.h>
+#include <test/util/xoroshiro128plusplus.h>
+
+#include <cstdint>
+#include <tuple>
+#include <vector>
+
+namespace {
+
+template <std::size_t MAX_BLOCK_SIZE_BYTES, std::size_t ALIGN_BYTES>
+class PoolResourceFuzzer
+{
+    FuzzedDataProvider& m_provider;
+    PoolResource<MAX_BLOCK_SIZE_BYTES, ALIGN_BYTES> m_test_resource;
+    uint64_t m_sequence{0};
+    size_t m_total_allocated{};
+
+    struct Entry {
+        Span<std::byte> span;
+        size_t alignment;
+        uint64_t seed;
+
+        Entry(Span<std::byte> s, size_t a, uint64_t se) : span(s), alignment(a), seed(se) {}
+    };
+
+    std::vector<Entry> m_entries;
+
+public:
+    PoolResourceFuzzer(FuzzedDataProvider& provider)
+        : m_provider{provider},
+          m_test_resource{provider.ConsumeIntegralInRange<size_t>(MAX_BLOCK_SIZE_BYTES, 262144)}
+    {
+    }
+
+    void Allocate(size_t size, size_t alignment)
+    {
+        assert(size > 0);                           // Must allocate at least 1 byte.
+        assert(alignment > 0);                      // Alignment must be at least 1.
+        assert((alignment & (alignment - 1)) == 0); // Alignment must be power of 2.
+        assert((size & (alignment - 1)) == 0);      // Size must be a multiple of alignment.
+
+        auto span = Span(static_cast<std::byte*>(m_test_resource.Allocate(size, alignment)), size);
+        m_total_allocated += size;
+
+        auto ptr_val = reinterpret_cast<std::uintptr_t>(span.data());
+        assert((ptr_val & (alignment - 1)) == 0);
+
+        uint64_t seed = m_sequence++;
+        RandomContentFill(m_entries.emplace_back(span, alignment, seed));
+    }
+
+    void
+    Allocate()
+    {
+        if (m_total_allocated > 0x1000000) return;
+        size_t alignment_bits = m_provider.ConsumeIntegralInRange<size_t>(0, 7);
+        size_t alignment = 1 << alignment_bits;
+        size_t size_bits = m_provider.ConsumeIntegralInRange<size_t>(0, 16 - alignment_bits);
+        size_t size = m_provider.ConsumeIntegralInRange<size_t>(1U << size_bits, (1U << (size_bits + 1)) - 1U) << alignment_bits;
+        Allocate(size, alignment);
+    }
+
+    void RandomContentFill(Entry& entry)
+    {
+        XoRoShiRo128PlusPlus rng(entry.seed);
+        auto ptr = entry.span.data();
+        auto size = entry.span.size();
+
+        while (size >= 8) {
+            auto r = rng();
+            std::memcpy(ptr, &r, 8);
+            size -= 8;
+            ptr += 8;
+        }
+        if (size > 0) {
+            auto r = rng();
+            std::memcpy(ptr, &r, size);
+        }
+    }
+
+    void RandomContentCheck(const Entry& entry)
+    {
+        XoRoShiRo128PlusPlus rng(entry.seed);
+        auto ptr = entry.span.data();
+        auto size = entry.span.size();
+
+        std::byte buf[8];
+        while (size >= 8) {
+            auto r = rng();
+            std::memcpy(buf, &r, 8);
+            assert(std::memcmp(buf, ptr, 8) == 0);
+            size -= 8;
+            ptr += 8;
+        }
+        if (size > 0) {
+            auto r = rng();
+            std::memcpy(buf, &r, size);
+            assert(std::memcmp(buf, ptr, size) == 0);
+        }
+    }
+
+    void Deallocate(const Entry& entry)
+    {
+        auto ptr_val = reinterpret_cast<std::uintptr_t>(entry.span.data());
+        assert((ptr_val & (entry.alignment - 1)) == 0);
+        RandomContentCheck(entry);
+        m_total_allocated -= entry.span.size();
+        m_test_resource.Deallocate(entry.span.data(), entry.span.size(), entry.alignment);
+    }
+
+    void Deallocate()
+    {
+        if (m_entries.empty()) {
+            return;
+        }
+
+        size_t idx = m_provider.ConsumeIntegralInRange<size_t>(0, m_entries.size() - 1);
+        Deallocate(m_entries[idx]);
+        if (idx != m_entries.size() - 1) {
+            m_entries[idx] = std::move(m_entries.back());
+        }
+        m_entries.pop_back();
+    }
+
+    void Clear()
+    {
+        while (!m_entries.empty()) {
+            Deallocate();
+        }
+
+        PoolResourceTester::CheckAllDataAccountedFor(m_test_resource);
+    }
+
+    void Fuzz()
+    {
+        LIMITED_WHILE(m_provider.ConsumeBool(), 10000)
+        {
+            CallOneOf(
+                m_provider,
+                [&] { Allocate(); },
+                [&] { Deallocate(); });
+        }
+        Clear();
+    }
+};
+
+
+} // namespace
+
+FUZZ_TARGET(pool_resource)
+{
+    FuzzedDataProvider provider(buffer.data(), buffer.size());
+    CallOneOf(
+        provider,
+        [&] { PoolResourceFuzzer<128, 1>{provider}.Fuzz(); },
+        [&] { PoolResourceFuzzer<128, 2>{provider}.Fuzz(); },
+        [&] { PoolResourceFuzzer<128, 4>{provider}.Fuzz(); },
+        [&] { PoolResourceFuzzer<128, 8>{provider}.Fuzz(); },
+
+        [&] { PoolResourceFuzzer<8, 8>{provider}.Fuzz(); },
+        [&] { PoolResourceFuzzer<16, 16>{provider}.Fuzz(); },
+
+        [&] { PoolResourceFuzzer<256, alignof(max_align_t)>{provider}.Fuzz(); },
+        [&] { PoolResourceFuzzer<256, 64>{provider}.Fuzz(); });
+}