https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84766
Bug ID: 84766
Summary: __verbose_terminate_handler mistakes parallel
unhandled exceptions for recursive std::terminate()
calls
Product: gcc
Version: 7.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: anovak at soe dot ucsc.edu
Target Milestone: ---
The default terminate handler, __gnu_cxx::__verbose_terminate_handler(), in
gcc/libstdc++-v3/libsupc++/vterminate.cc, begins thusly:
void __verbose_terminate_handler()
{
static bool terminating;
if (terminating)
{
fputs("terminate called recursively\n", stderr);
abort ();
}
terminating = true;
...
The function uses a static bool flag, which it checks. If it is already set, it
knows std::terminate() has already been called, so it complains of a recursive
std::terminate() call and immediately aborts. If it isn't already set, it
continues with printing some exception info before calling abort().
However, this function doesn't seem to handle the case of multiple threads. It
is possible for one thread to have an unhandled exception, causing terminate
(and the handler) to be called, and then for a second thread to also have an
unhandled exception before abort() can stop the process. That second thread
will also call terminate, and the handler will report a "recursive" call to
terminate, even though the call really wasn't recursive. This also prevents the
second thread from outputting a nice formatted exception message.
Can the terminating flag be made thread local? Or can the message be changed to
describe "concurrent" or "reentrant" calls to terminate instead of "recursive"
ones?
