Peerplays_Blockchain/peerplays-fc
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Instead of canceling the read_loop, close the socket and wait for the read_loop to finish as a result. This prevents the receive_from from writing into the buffer (which is on the stack!) after the task is canceled. This caused nasty intermittent exception stack unwind errors.

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This commit is contained in:
dnotestein 2014-09-08 17:23:03 -04:00
parent 881903c1be
commit c79cbdae8e
1 changed files with 16 additions and 4 deletions
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20
src/network/ntp.cpp
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@ -30,11 +30,13 @@ namespace fc
fc::future<void> _request_time_task_done; fc::future<void> _request_time_task_done;
bool _shutting_down_ntp;
ntp_impl() : ntp_impl() :
_ntp_thread("ntp"), _ntp_thread("ntp"),
_request_interval_sec( 60*60 /* 1 hr */), _request_interval_sec( 60*60 /* 1 hr */),
_last_ntp_delta_microseconds(0) _last_ntp_delta_microseconds(0),
_shutting_down_ntp(false)
{ {
_last_ntp_delta_initialized = false; _last_ntp_delta_initialized = false;
_ntp_hosts.push_back( std::make_pair( "pool.ntp.org",123 ) ); _ntp_hosts.push_back( std::make_pair( "pool.ntp.org",123 ) );
@ -143,11 +145,16 @@ namespace fc
} }
catch (...) catch (...)
{ {
//don't restart read loop if we're destructing
if (_shutting_down_ntp)
return;
//swallow any other exception and restart loop //swallow any other exception and restart loop
elog("unexpected exception in read_loop, going to restart it."); elog("unexpected exception in read_loop, going to restart it.");
} }
_sock.close(); _sock.close();
fc::usleep(fc::seconds(_request_interval_sec)); fc::usleep(fc::seconds(1));
if (_shutting_down_ntp)
return;
} //outer while loop } //outer while loop
} //end read_loop() } //end read_loop()
}; };
@ -165,6 +172,7 @@ namespace fc
ntp::~ntp() ntp::~ntp()
{ {
my->_ntp_thread.async([=](){ my->_ntp_thread.async([=](){
my->_shutting_down_ntp = true;
try try
{ {
my->_request_time_task_done.cancel_and_wait("ntp object is destructing"); my->_request_time_task_done.cancel_and_wait("ntp object is destructing");
@ -177,7 +185,11 @@ namespace fc
{ {
wlog( "Exception thrown while shutting down NTP's request_time_task, ignoring" ); wlog( "Exception thrown while shutting down NTP's request_time_task, ignoring" );
} }
//instead of canceling task, we close the socket and wait for the task to end because receive_from will throw
//if we just canceled the task, the receive_from would likely complete after the recv_buf was gone and we would get a random write into our stack.
my->_sock.close();
my->_read_loop_done.wait(); //wait for socket to close
#if 0
try try
{ {
my->_read_loop_done.cancel_and_wait("ntp object is destructing"); my->_read_loop_done.cancel_and_wait("ntp object is destructing");
@ -190,7 +202,7 @@ namespace fc
{ {
wlog( "Exception thrown while shutting down NTP's read_loop, ignoring" ); wlog( "Exception thrown while shutting down NTP's read_loop, ignoring" );
} }
#endif
}, "ntp_shutdown_task").wait(); }, "ntp_shutdown_task").wait();
} }