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Crash handler registration does not work correctly #150

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Merged
merged 1 commit into from
Nov 8, 2024
Merged

Crash handler registration does not work correctly #150

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13 changes: 8 additions & 5 deletions ddprof-lib/src/main/cpp/profiler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@
// The instance is not deleted on purpose, since profiler structures
// can be still accessed concurrently during VM termination
Profiler *const Profiler::_instance = new Profiler();
volatile bool Profiler::_signals_initialized = false;

static void (*orig_trapHandler)(int signo, siginfo_t *siginfo, void *ucontext);
static void (*orig_segvHandler)(int signo, siginfo_t *siginfo, void *ucontext);
Expand Down Expand Up @@ -975,11 +976,13 @@ bool Profiler::crashHandler(int signo, siginfo_t *siginfo, void *ucontext) {

void Profiler::setupSignalHandlers() {
// do not re-run the signal setup (run only when VM has not been loaded yet)
if (VM::java_version() > 0 && !VM::loaded()) {
// HotSpot and J9 tolerate interposed SIGSEGV/SIGBUS handler; other JVMs
// probably not
orig_segvHandler = OS::replaceSigsegvHandler(segvHandler);
orig_busHandler = OS::replaceSigbusHandler(busHandler);
if (__sync_bool_compare_and_swap(&_signals_initialized, false, true)) {
if (VM::isHotspot() || VM::isOpenJ9()) {
// HotSpot and J9 tolerate interposed SIGSEGV/SIGBUS handler; other JVMs
// probably not
orig_segvHandler = OS::replaceSigsegvHandler(segvHandler);
orig_busHandler = OS::replaceSigbusHandler(busHandler);
}
}
}

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3 changes: 3 additions & 0 deletions ddprof-lib/src/main/cpp/profiler.h
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Expand Up @@ -66,6 +66,9 @@ class Profiler {
friend VM;

private:
// signal handlers
static volatile bool _signals_initialized;

Mutex _state_lock;
State _state;
// class unload hook
Expand Down
12 changes: 12 additions & 0 deletions ddprof-lib/src/main/cpp/vmEntry.cpp
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Expand Up @@ -227,6 +227,12 @@ bool VM::init(JavaVM *vm, bool attach) {
prop = NULL;
}
if (_jvmti->GetSystemProperty("java.vm.version", &prop) == 0) {
if (_java_version == 0) {
// java.runtime.version was not found; try using java.vm.version to extract the information
JavaFullVersion version = JavaVersionAccess::get_java_version(prop);
_java_version = version.major;
_java_update_version = version.update;
}
_hotspot_version = JavaVersionAccess::get_hotspot_version(prop);
_jvmti->Deallocate((unsigned char *)prop);
prop = NULL;
Expand All @@ -236,6 +242,12 @@ bool VM::init(JavaVM *vm, bool attach) {
_jvmti->Deallocate((unsigned char *)prop);
}

if (_java_version == 0 && _hotspot_version > 0) {
// sanity fallback:
// - if we failed to resolve the _java_version but have _hotspot_version, let's use the hotspot version as java version
_java_version = _hotspot_version;
}

_can_sample_objects = !_hotspot || hotspot_version() >= 11;

CodeCache *lib =
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