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8029178: Parallel class loading test anonymous-simple gets SIGSEGV in Metaspace::contains

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Metaspace::contains cannot look at purged metaspaces while CMS concurrently deallocates them.

Reviewed-by: mgerdin, sspitsyn, jmasa
This commit is contained in:
Coleen Phillimore 2014-01-07 13:26:56 -05:00
parent 3e537df17c
commit 469f290817
10 changed files with 43 additions and 54 deletions
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21
hotspot/src/share/vm/classfile/classLoaderData.cpp
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@ -648,12 +648,12 @@ GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
return array;
}
#ifndef PRODUCT
// for debugging and hsfind(x)
bool ClassLoaderDataGraph::contains(address x) {
// I think we need the _metaspace_lock taken here because the class loader
// data graph could be changing while we are walking it (new entries added,
// new entries being unloaded, etc).
// For profiling and hsfind() only. Otherwise, this is unsafe (and slow). This
// is done lock free to avoid lock inversion problems. It is safe because
// new ClassLoaderData are added to the end of the CLDG, and only removed at
// safepoint. The _unloading list can be deallocated concurrently with CMS so
// this doesn't look in metaspace for classes that have been unloaded.
bool ClassLoaderDataGraph::contains(const void* x) {
if (DumpSharedSpaces) {
// There are only two metaspaces to worry about.
ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
@ -670,16 +670,11 @@ bool ClassLoaderDataGraph::contains(address x) {
}
}
// Could also be on an unloading list which is okay, ie. still allocated
// for a little while.
for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) {
if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) {
return true;
}
}
// Do not check unloading list because deallocation can be concurrent.
return false;
}
#ifndef PRODUCT
bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
if (loader_data == data) {