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8209950: SIGBUS in CodeHeapState::print_names()

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Reviewed-by: thartmann, kvn
This commit is contained in:
Lutz Schmidt 2018-08-30 09:34:10 +02:00
parent 05b8f66dff
commit af1ce0a659
4 changed files with 25 additions and 11 deletions
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5
src/hotspot/share/code/codeHeapState.cpp
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@ -2168,9 +2168,8 @@ void CodeHeapState::print_names(outputStream* out, CodeHeap* heap) {
// this_blob->as_nmethod_or_null() is safe. Inlined, maybe invisible on stack.
nmethod* nm = this_blob->as_nmethod_or_null();
Method* method = (nm == NULL) ? NULL : nm->method(); // may be uninitialized, i.e. != NULL, but invalid
if ((nm != NULL) && (method != NULL) && (cbType != nMethod_dead) && (cbType != nMethod_inconstruction) &&
os::is_readable_pointer(method) && os::is_readable_pointer(method->constants())) {
if (CompiledMethod::nmethod_access_is_safe(nm)) {
Method* method = nm->method();
ResourceMark rm;
//---< collect all data to locals as quickly as possible >---
unsigned int total_size = nm->total_size();

15
src/hotspot/share/code/compiledMethod.cpp
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@ -619,3 +619,18 @@ void CompiledMethod::do_unloading_parallel_postponed() {
}
}
}
// Iterating over all nmethods, e.g. with the help of CodeCache::nmethods_do(fun) was found
// to not be inherently safe. There is a chance that fields are seen which are not properly
// initialized. This happens despite the fact that nmethods_do() asserts the CodeCache_lock
// to be held.
// To bundle knowledge about necessary checks in one place, this function was introduced.
// It is not claimed that these checks are sufficient, but they were found to be necessary.
bool CompiledMethod::nmethod_access_is_safe(nmethod* nm) {
Method* method = (nm == NULL) ? NULL : nm->method(); // nm->method() may be uninitialized, i.e. != NULL, but invalid
return (nm != NULL) && (method != NULL) && (method->signature() != NULL) &&
!nm->is_zombie() && !nm->is_not_installed() &&
os::is_readable_pointer(method) &&
os::is_readable_pointer(method->constants()) &&
os::is_readable_pointer(method->signature());
}

2
src/hotspot/share/code/compiledMethod.hpp
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@ -238,6 +238,8 @@ public:
return _mark_for_deoptimization_status != deoptimize_noupdate;
}
static bool nmethod_access_is_safe(nmethod* nm);
// tells whether frames described by this nmethod can be deoptimized
// note: native wrappers cannot be deoptimized.
bool can_be_deoptimized() const { return is_java_method(); }

14
src/hotspot/share/runtime/sharedRuntime.cpp
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@ -2135,16 +2135,14 @@ class MethodArityHistogram {
static int _max_size; // max. arg size seen
static void add_method_to_histogram(nmethod* nm) {
// These checks are taken from CodeHeapState::print_names()
Method* m = (nm == NULL) ? NULL : nm->method(); // nm->method() may be uninitialized, i.e. != NULL, but invalid
if ((nm != NULL) && (m != NULL) && !nm->is_zombie() && !nm->is_not_installed() &&
os::is_readable_pointer(m) && os::is_readable_pointer(m->constants())) {
ArgumentCount args(m->signature());
int arity = args.size() + (m->is_static() ? 0 : 1);
int argsize = m->size_of_parameters();
if (CompiledMethod::nmethod_access_is_safe(nm)) {
Method* method = nm->method();
ArgumentCount args(method->signature());
int arity = args.size() + (method->is_static() ? 0 : 1);
int argsize = method->size_of_parameters();
arity = MIN2(arity, MAX_ARITY-1);
argsize = MIN2(argsize, MAX_ARITY-1);
int count = nm->method()->compiled_invocation_count();
int count = method->compiled_invocation_count();
_arity_histogram[arity] += count;
_size_histogram[argsize] += count;
_max_arity = MAX2(_max_arity, arity);