Jiri Danek created PROTON-1591:
----------------------------------
Summary: [proton-cpp] Scheduling task from a scheduled task will
deadlock
Key: PROTON-1591
URL: https://issues.apache.org/jira/browse/PROTON-1591
Project: Qpid Proton
Issue Type: Bug
Components: cpp-binding
Environment: commit 6a57a8c986fbf86ad8ad109d673a89a5ae84c544
(upstream/master)
Author: Cliff Jansen <cliffjan...@apache.org>
Date: Thu Sep 14 23:29:14 2017 -0700
PROTON-1349: completed and improved implementation, but still fails many
tests
Reporter: Jiri Danek
Assignee: Cliff Jansen
Modify the {{cpp/simple_send.cpp}} example the following way
{code}
diff --git a/examples/cpp/simple_send.cpp b/examples/cpp/simple_send.cpp
index a4c2272d..92e60ee0 100644
--- a/examples/cpp/simple_send.cpp
+++ b/examples/cpp/simple_send.cpp
@@ -29,9 +29,11 @@
#include <proton/messaging_handler.hpp>
#include <proton/tracker.hpp>
#include <proton/types.hpp>
+#include <proton/work_queue.hpp>
#include <iostream>
#include <map>
+#include <functional>
#include "fake_cpp11.hpp"
@@ -45,15 +47,28 @@ class simple_send : public proton::messaging_handler {
int confirmed;
int total;
+ std::function<void()> callback;
+
public:
simple_send(const std::string &s, const std::string &u, const std::string
&p, int c) :
- url(s), user(u), password(p), sent(0), confirmed(0), total(c) {}
+ url(s), user(u), password(p), sent(0), confirmed(0), total(c) {
+ callback = [this]() {
+ std::cout << "Entering callback" << std::endl;
+// TODO: uncomment one of the two commands below
+//****************************************************************************************************
+// sender.container().stop();
+// sender.container().schedule(1 * proton::duration::SECOND,
proton::work(callback));
+//****************************************************************************************************
+ std::cout << "Leaving callback" << std::endl;
+ };
+ }
void on_container_start(proton::container &c) OVERRIDE {
proton::connection_options co;
if (!user.empty()) co.user(user);
if (!password.empty()) co.password(password);
sender = c.open_sender(url, co);
+ c.schedule(1 * proton::duration::SECOND, proton::work(callback));
}
void on_sendable(proton::sender &s) OVERRIDE {
{code}
Now uncomment one of the two commented out commands. Either to stop the
container from the inside scheduled task, or to schedule new task from inside
the scheduled task. When executed, the program will deadlock.
{noformat}
Program received signal SIGINT, Interrupt.
0x00007ffff68ef6dc in __lll_lock_wait () from
/nix/store/l48biijfr1j6d5kdg911051x2phfjrz7-glibc-2.25/lib/libpthread.so.0
(gdb) bt
#0 0x00007ffff68ef6dc in __lll_lock_wait () from
/nix/store/l48biijfr1j6d5kdg911051x2phfjrz7-glibc-2.25/lib/libpthread.so.0
#1 0x00007ffff68e88e5 in pthread_mutex_lock () from
/nix/store/l48biijfr1j6d5kdg911051x2phfjrz7-glibc-2.25/lib/libpthread.so.0
#2 0x00007ffff7baf1e8 in __gthread_mutex_lock (__mutex=0x61e148) at
/nix/store/pdidaf83cvkrgx8xjgjdnl5m1naqjbfk-gcc-7.1.0/include/c++/7.1.0/x86_64-pc-linux-gnu/bits/gthr-default.h:748
#3 std::mutex::lock (this=0x61e148) at
/nix/store/pdidaf83cvkrgx8xjgjdnl5m1naqjbfk-gcc-7.1.0/include/c++/7.1.0/bits/std_mutex.h:103
#4 std::lock_guard<std::mutex>::lock_guard (__m=..., this=<synthetic pointer>)
at
/nix/store/pdidaf83cvkrgx8xjgjdnl5m1naqjbfk-gcc-7.1.0/include/c++/7.1.0/bits/std_mutex.h:162
#5 proton::container::impl::schedule (this=this@entry=0x61e140, delay=...,
delay@entry=..., f=...) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/proactor_container_impl.cpp:399
#6 0x00007ffff7baccc8 in proton::container::schedule
(this=this@entry=0x7fffffffc668, d=..., f=...) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/container.cpp:109
#7 0x00000000004065f9 in
simple_send::simple_send(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&,
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >
const&, std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&, int)::{lambda()#1}::operator()() const
(__closure=<optimized out>) at
/home/jdanek/Work/repos/qpid-proton/examples/cpp/simple_send.cpp:58
#8 std::_Function_handler<void (),
simple_send::simple_send(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&,
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >
const&, std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&, int)::{lambda()#1}>::_M_invoke(std::_Any_data
const&) (__functor=...) at
/nix/store/pdidaf83cvkrgx8xjgjdnl5m1naqjbfk-gcc-7.1.0/include/c++/7.1.0/bits/std_function.h:316
#9 0x00007ffff7baf706 in std::function<void ()>::operator()() const
(this=<optimized out>) at
/nix/store/pdidaf83cvkrgx8xjgjdnl5m1naqjbfk-gcc-7.1.0/include/c++/7.1.0/bits/std_function.h:706
#10 proton::work::operator() (this=<optimized out>) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/include/proton/work_queue.hpp:59
#11 proton::container::impl::run_timer_jobs (this=this@entry=0x61e140) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/proactor_container_impl.cpp:439
#12 0x00007ffff7bafe10 in proton::container::impl::handle
(this=this@entry=0x61e140, event=0x625590) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/proactor_container_impl.cpp:478
#13 0x00007ffff7baffeb in proton::container::impl::thread
(this=this@entry=0x61e140) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/proactor_container_impl.cpp:613
#14 0x00007ffff7bb0393 in proton::container::impl::run (this=0x61e140,
threads=threads@entry=1) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/proactor_container_impl.cpp:651
#15 0x00007ffff7bac74d in proton::container::run
(this=this@entry=0x7fffffffc668) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/container.cpp:83
#16 0x0000000000404d2f in main (argc=<optimized out>, argv=<optimized out>) at
/home/jdanek/Work/repos/qpid-proton/examples/cpp/simple_send.cpp:115
#17 0x00007ffff6b1d530 in __libc_start_main () from
/nix/store/l48biijfr1j6d5kdg911051x2phfjrz7-glibc-2.25/lib/libc.so.6
#18 0x00000000004051aa in _start () at ../sysdeps/x86_64/start.S:120
{noformat}
The lock was first acquired here
{noformat}
(gdb) frame 12
#12 0x00007ffff7bafe10 in proton::container::impl::handle
(this=this@entry=0x61e140, event=0x625590) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/proactor_container_impl.cpp:478
478 run_timer_jobs();
(gdb) l
473
474 case PN_PROACTOR_TIMEOUT: {
475 GUARD(lock_);
476 // Can get an immediate timeout, if we have a container event
loop inject
477 if ( deferred_.size()>0 ) {
478 run_timer_jobs();
479 }
480
481 // Run every container event loop job
482 // This is not at all efficient and single threads all these
jobs, but it does correctly
{noformat}
and the thread tries to reacquire it again here (this is the schedule task from
scheduled task case)
{noformat}
(gdb) frame 5
#5 proton::container::impl::schedule (this=this@entry=0x61e140, delay=...,
delay@entry=..., f=...) at
/home/jdanek/Work/repos/qpid-proton/proton-c/bindings/cpp/src/proactor_container_impl.cpp:399
399 GUARD(lock_);
(gdb) l
394 lc.listen_handler_ = &lh;
395 return proton::listener(listener);
396 }
397
398 void container::impl::schedule(duration delay, work f) {
399 GUARD(lock_);
400 timestamp now = timestamp::now();
401
402 // Record timeout; Add callback to timeout sorted list
403 scheduled s = {now+delay, f};
{noformat}
This reproducer is based on larger application which was using the previous
version of the task scheduling API and which was now updated to compile with
Proton 0.18.
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