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Stop using event_base_once().

Browse Source 
This function leaks memory when the event_base is freed before the
event itself fires.  That's not harmful, but it's annoying when
trying to debug other memory leaks.

Fixes bug 24584; bugfix on 0.2.8.1-alpha.
This commit is contained in:
Nick Mathewson 2017-12-11 12:21:00 -05:00
parent ea929e8456
commit f205dabf7a
2 changed files with 21 additions and 6 deletions
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5
changes/bug24584 Normal file
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@ -0,0 +1,5 @@
o Minor bugfixes (memory cleanup):
- Avoid possible at-exit memory leaks related to use of Libevent's
event_base_once() function. (This function tends to leak memory
if the event_base is closed before the event fires.) Fixes bug 24584;
bugfix on 0.2.8.1-alpha.

22
src/or/main.c
View File

@ -666,6 +666,9 @@ tell_event_loop_to_run_external_code(void)
}
}
/** Event to run 'shutdown did not work callback'. */
static struct event *shutdown_did_not_work_event = NULL;
/** Failsafe measure that should never actually be necessary: If
* tor_shutdown_event_loop_and_exit() somehow doesn't successfully exit the
* event loop, then this callback will kill Tor with an assertion failure
@ -699,9 +702,10 @@ tor_shutdown_event_loop_and_exit(int exitcode)
* exit normally. */
/* XXXX We should consider this code if it's never used. */
struct timeval ten_seconds = { 10, 0 };
event_base_once(tor_libevent_get_base(), -1, EV_TIMEOUT,
shutdown_did_not_work_callback, NULL,
&ten_seconds);
shutdown_did_not_work_event = tor_evtimer_new(
tor_libevent_get_base(),
shutdown_did_not_work_callback, NULL);
event_add(shutdown_did_not_work_event, &ten_seconds);
/* Unlike loopexit, loopbreak prevents other callbacks from running. */
tor_event_base_loopbreak(tor_libevent_get_base());
@ -1341,6 +1345,8 @@ find_periodic_event(const char *name)
return NULL;
}
/** Event to run initialize_periodic_events_cb */
static struct event *initialize_periodic_events_event = NULL;
/** Helper, run one second after setup:
* Initializes all members of periodic_events and starts them running.
*
@ -1352,6 +1358,7 @@ initialize_periodic_events_cb(evutil_socket_t fd, short events, void *data)
(void) fd;
(void) events;
(void) data;
tor_event_free(initialize_periodic_events_event);
int i;
for (i = 0; periodic_events[i].name; ++i) {
periodic_event_launch(&periodic_events[i]);
@ -1380,9 +1387,10 @@ initialize_periodic_events(void)
NAMED_CALLBACK(check_dns_honesty);
struct timeval one_second = { 1, 0 };
event_base_once(tor_libevent_get_base(), -1, EV_TIMEOUT,
initialize_periodic_events_cb, NULL,
&one_second);
initialize_periodic_events_event = tor_evtimer_new(
tor_libevent_get_base(),
initialize_periodic_events_cb, NULL);
event_add(initialize_periodic_events_event, &one_second);
}
STATIC void
@ -3384,6 +3392,8 @@ tor_free_all(int postfork)
periodic_timer_free(second_timer);
teardown_periodic_events();
periodic_timer_free(refill_timer);
tor_event_free(shutdown_did_not_work_event);
tor_event_free(initialize_periodic_events_event);
if (!postfork) {
release_lockfile();