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8298377: JfrVframeStream causes deadlocks in ZGC

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Co-authored-by: Erik Österlund <eosterlund@openjdk.org>
Reviewed-by: eosterlund, mgronlun
This commit is contained in:
Stefan Karlsson 2023-01-19 13:49:14 +00:00
parent 1084fd24eb
commit 453dbd12ee
2 changed files with 24 additions and 1 deletions
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11
src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp
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@ -41,6 +41,7 @@
#include "runtime/javaThread.inline.hpp"
#include "runtime/os.hpp"
#include "runtime/semaphore.hpp"
#include "runtime/stackWatermark.hpp"
#include "runtime/suspendedThreadTask.hpp"
#include "runtime/threadCrashProtection.hpp"
#include "runtime/threadSMR.hpp"
@ -256,6 +257,11 @@ void JfrNativeSamplerCallback::call() {
}
bool JfrThreadSampleClosure::sample_thread_in_java(JavaThread* thread, JfrStackFrame* frames, u4 max_frames) {
// Process the oops in the thread head before calling into code that wants to
// stack walk over Loom continuations. The stack walking code will otherwise
// skip frames in stack chunks on the Java heap.
StackWatermarkSet::start_processing(thread, StackWatermarkKind::gc);
OSThreadSampler sampler(thread, *this, frames, max_frames);
sampler.take_sample();
/* We don't want to allocate any memory using malloc/etc while the thread
@ -274,6 +280,11 @@ bool JfrThreadSampleClosure::sample_thread_in_java(JavaThread* thread, JfrStackF
}
bool JfrThreadSampleClosure::sample_thread_in_native(JavaThread* thread, JfrStackFrame* frames, u4 max_frames) {
// Process the oops in the thread head before calling into code that wants to
// stack walk over Loom continuations. The stack walking code will otherwise
// skip frames in stack chunks on the Java heap.
StackWatermarkSet::start_processing(thread, StackWatermarkKind::gc);
JfrNativeSamplerCallback cb(*this, thread, frames, max_frames);
if (JfrOptionSet::sample_protection()) {
ThreadCrashProtection crash_protection;

14
src/hotspot/share/jfr/recorder/stacktrace/jfrStackTrace.cpp
View File

@ -148,11 +148,23 @@ class JfrVframeStream : public vframeStreamCommon {
void next_vframe();
};
static RegisterMap::WalkContinuation walk_continuation(JavaThread* jt) {
// NOTE: WalkContinuation::skip, because of interactions with ZGC relocation
// and load barriers. This code is run while generating stack traces for
// the ZPage allocation event, even when ZGC is relocating objects.
// When ZGC is relocating, it is forbidden to run code that performs
// load barriers. With WalkContinuation::include, we visit heap stack
// chunks and could be using load barriers.
return (UseZGC && !StackWatermarkSet::processing_started(jt))
? RegisterMap::WalkContinuation::skip
: RegisterMap::WalkContinuation::include;
}
JfrVframeStream::JfrVframeStream(JavaThread* jt, const frame& fr, bool stop_at_java_call_stub, bool async_mode) :
vframeStreamCommon(RegisterMap(jt,
RegisterMap::UpdateMap::skip,
RegisterMap::ProcessFrames::skip,
RegisterMap::WalkContinuation::include)),
walk_continuation(jt))),
_cont_entry(JfrThreadLocal::is_vthread(jt) ? jt->last_continuation() : nullptr),
_async_mode(async_mode), _vthread(JfrThreadLocal::is_vthread(jt)) {
assert(!_vthread || _cont_entry != nullptr, "invariant");