Guard chaos harness malloc checking and gate hotspot in raw-pointer test

Detect glibc >= 2.34 and preload libc_malloc_debug (or fail clearly) so
MALLOC_CHECK_ actually takes effect; check patch-dd-java-agent.sh's exit
status directly instead of inferring success from JAR presence; force
Hotspot on in FalseForRawAsgctBciWithBit30SetButNoEncodedMarker so the
test exercises isRawPointer()'s HotSpot-gated path.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: jbachorik

ddprof-lib/src/test/cpp/frame_ut.cpp

@@ -182,6 +182,7 @@ TEST(FrameTypeIsRawPointerTest, FalseForRawAsgctBciWithBit30SetButNoEncodedMarke
     // and therefore never set ENCODED_MASK; only encode(..., rawPointer=true)
     // (HotSpot-only, per its own assert) is allowed to set RAW_POINTER_MASK.
     int rawAsgctBciWithBit30 = 1 << 30;
+    VMHotspotGuard hotspot(true);
     EXPECT_FALSE(FrameType::isRawPointer(rawAsgctBciWithBit30))
         << "isRawPointer() must require ENCODED_MASK (bit 20) before trusting bit 30, "
         << "otherwise raw ASGCT BCIs that never went through encode() can false-positive";

utils/run-chaos-harness.sh

@@ -123,12 +123,15 @@ fi
 # Patch dd-java-agent.jar with the locally built ddprof contents so the
 # agent's (relocated) profiler classes match the version under test.
 PATCHED_AGENT="${WORK_DIR}/dd-java-agent-patched.jar"
-DD_AGENT_JAR="${DD_AGENT_JAR}" DDPROF_JAR="${DDPROF_JAR}" OUTPUT_JAR="${PATCHED_AGENT}" \
-  "${ROOT}/utils/patch-dd-java-agent.sh"
-if [ ! -f "${PATCHED_AGENT}" ]; then
+if ! DD_AGENT_JAR="${DD_AGENT_JAR}" DDPROF_JAR="${DDPROF_JAR}" OUTPUT_JAR="${PATCHED_AGENT}" \
+  "${ROOT}/utils/patch-dd-java-agent.sh"; then
   echo "FAIL:dd-java-agent patching failed" >&2
   exit 1
 fi
+if [ ! -f "${PATCHED_AGENT}" ]; then
+  echo "FAIL:dd-java-agent patching reported success but output jar is missing" >&2
+  exit 1
+fi
 
 case $CONFIG in
   profiler)
@@ -163,6 +166,23 @@ case $ALLOCATOR in
     # (mirrors the tcmalloc/jemalloc tuning below).
     export MALLOC_ARENA_MAX=2
     export MALLOC_TRIM_THRESHOLD_=65536
+    # glibc >= 2.34 moved MALLOC_CHECK_ support out of the main libc; it is a
+    # silent no-op unless libc_malloc_debug is preloaded (see glibc's "Heap
+    # Consistency Checking" docs). Detect that case and preload the debug
+    # library explicitly, rather than silently running with corruption
+    # detection disabled.
+    if command -v ldd >/dev/null 2>&1; then
+      GLIBC_VERSION=$(ldd --version 2>/dev/null | head -1 | grep -oE '[0-9]+\.[0-9]+$')
+      if [ -n "${GLIBC_VERSION}" ] && [ "$(printf '%s\n' "2.34" "${GLIBC_VERSION}" | sort -V | head -1)" = "2.34" ]; then
+        MALLOC_DEBUG_LIB=$(find /usr/lib/ /usr/lib64/ /lib/ /lib64/ -name 'libc_malloc_debug.so*' 2>/dev/null | head -1)
+        if [ -z "${MALLOC_DEBUG_LIB}" ]; then
+          echo "FAIL:glibc ${GLIBC_VERSION} requires libc_malloc_debug to be preloaded for MALLOC_CHECK_ to take effect, but it could not be found" >&2
+          exit 1
+        fi
+        export LD_PRELOAD="${MALLOC_DEBUG_LIB}${LD_PRELOAD:+:${LD_PRELOAD}}"
+        echo "glibc ${GLIBC_VERSION} detected — preloading ${MALLOC_DEBUG_LIB} for MALLOC_CHECK_"
+      fi
+    fi
     ;;
   tcmalloc)
     export LD_PRELOAD=$(find /usr/lib/ /usr/lib64/ /opt/homebrew/lib/ /usr/local/lib/ -name 'libtcmalloc_minimal.so.4' -o -name 'libtcmalloc.dylib' 2>/dev/null | head -1)