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From e7a2611c555e03314ac4f7960044b05cce040364 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Thu, 31 Jul 2014 11:38:11 +1000
Subject: [PATCH] 3905. [bug] Address deadlock between view.c and adb.c. [RT
#36341]
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Original-commit: 5e746ab61ed8158f784b86111fef95581a08b7dd
Signed-off-by: Petr Menšík <pemensik@redhat.com>
---
lib/dns/adb.c | 57 +++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 41 insertions(+), 16 deletions(-)
diff --git a/lib/dns/adb.c b/lib/dns/adb.c
index a6da94d..ac89e66 100644
--- a/lib/dns/adb.c
+++ b/lib/dns/adb.c
@@ -15,8 +15,6 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
-/* $Id: adb.c,v 1.264 2011/12/05 17:10:51 each Exp $ */
-
/*! \file
*
* \note
@@ -157,7 +155,7 @@ struct dns_adb {
unsigned int *entry_refcnt;
isc_event_t cevent;
- isc_boolean_t cevent_sent;
+ isc_boolean_t cevent_out;
isc_boolean_t shutting_down;
isc_eventlist_t whenshutdown;
isc_event_t growentries;
@@ -322,6 +320,7 @@ static inline isc_boolean_t unlink_entry(dns_adb_t *, dns_adbentry_t *);
static isc_boolean_t kill_name(dns_adbname_t **, isc_eventtype_t);
static void water(void *, int);
static void dump_entry(FILE *, dns_adbentry_t *, isc_boolean_t, isc_stdtime_t);
+static void shutdown_task(isc_task_t *task, isc_event_t *ev);
/*
* MUST NOT overlap DNS_ADBFIND_* flags!
@@ -1499,10 +1498,13 @@ check_exit(dns_adb_t *adb) {
* If there aren't any external references either, we're
* done. Send the control event to initiate shutdown.
*/
- INSIST(!adb->cevent_sent); /* Sanity check. */
+ INSIST(!adb->cevent_out); /* Sanity check. */
+ ISC_EVENT_INIT(&adb->cevent, sizeof(adb->cevent), 0, NULL,
+ DNS_EVENT_ADBCONTROL, shutdown_task, adb,
+ adb, NULL, NULL);
event = &adb->cevent;
isc_task_send(adb->task, &event);
- adb->cevent_sent = ISC_TRUE;
+ adb->cevent_out = ISC_TRUE;
}
}
@@ -2431,10 +2433,9 @@ dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_timermgr_t *timermgr,
adb->view = view;
adb->taskmgr = taskmgr;
adb->next_cleanbucket = 0;
- ISC_EVENT_INIT(&adb->cevent, sizeof(adb->cevent), 0, NULL,
- DNS_EVENT_ADBCONTROL, shutdown_task, adb,
- adb, NULL, NULL);
- adb->cevent_sent = ISC_FALSE;
+ ISC_EVENT_INIT(&adb->cevent, sizeof(adb->cevent),
+ 0, NULL, 0, NULL, NULL, NULL, NULL, NULL);
+ adb->cevent_out = ISC_FALSE;
adb->shutting_down = ISC_FALSE;
ISC_LIST_INIT(adb->whenshutdown);
@@ -2468,7 +2469,7 @@ dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_timermgr_t *timermgr,
"intializing table sizes to %u\n",
nbuckets[11]);
adb->nentries = nbuckets[11];
- adb->nnames= nbuckets[11];
+ adb->nnames = nbuckets[11];
}
@@ -2741,9 +2742,28 @@ dns_adb_whenshutdown(dns_adb_t *adb, isc_task_t *task, isc_event_t **eventp) {
UNLOCK(&adb->lock);
}
+static void
+shutdown_stage2(isc_task_t *task, isc_event_t *event) {
+ dns_adb_t *adb;
+
+ UNUSED(task);
+
+ adb = event->ev_arg;
+ INSIST(DNS_ADB_VALID(adb));
+
+ LOCK(&adb->lock);
+ INSIST(adb->shutting_down);
+ adb->cevent_out = ISC_FALSE;
+ (void)shutdown_names(adb);
+ (void)shutdown_entries(adb);
+ if (dec_adb_irefcnt(adb))
+ check_exit(adb);
+ UNLOCK(&adb->lock);
+}
+
void
dns_adb_shutdown(dns_adb_t *adb) {
- isc_boolean_t need_check_exit;
+ isc_event_t *event;
/*
* Shutdown 'adb'.
@@ -2754,11 +2774,16 @@ dns_adb_shutdown(dns_adb_t *adb) {
if (!adb->shutting_down) {
adb->shutting_down = ISC_TRUE;
isc_mem_setwater(adb->mctx, water, adb, 0, 0);
- need_check_exit = shutdown_names(adb);
- if (!need_check_exit)
- need_check_exit = shutdown_entries(adb);
- if (need_check_exit)
- check_exit(adb);
+ /*
+ * Isolate shutdown_names and shutdown_entries calls.
+ */
+ inc_adb_irefcnt(adb);
+ ISC_EVENT_INIT(&adb->cevent, sizeof(adb->cevent), 0, NULL,
+ DNS_EVENT_ADBCONTROL, shutdown_stage2, adb,
+ adb, NULL, NULL);
+ adb->cevent_out = ISC_TRUE;
+ event = &adb->cevent;
+ isc_task_send(adb->task, &event);
}
UNLOCK(&adb->lock);
--
2.9.3