From 05fa0ab676506e4453c81dc4773d42bd742168af Mon Sep 17 00:00:00 2001
From: Marek Vavrusa <marek.vavrusa@nic.cz>
Date: Mon, 13 Aug 2012 16:28:59 +0200
Subject: [PATCH] RCU locking order in xfr_client_start()
refs #1976
---
src/knot/server/xfr-handler.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/src/knot/server/xfr-handler.c b/src/knot/server/xfr-handler.c
index a76a7f49a0..9b8055ad22 100644
--- a/src/knot/server/xfr-handler.c
+++ b/src/knot/server/xfr-handler.c
@@ -788,6 +788,7 @@ static int xfr_client_start(xfrworker_t *w, knot_ns_xfr_t *data)
/* Enqueue to worker that has zone locked for XFR/IN. */
int ret = pthread_mutex_trylock(&zd->xfr_in.lock);
+ rcu_read_lock();
if (ret != 0) {
dbg_xfr_verb("xfr: XFR/IN switching to another thread, "
"zone '%s' is already in transfer\n",
@@ -807,6 +808,8 @@ static int xfr_client_start(xfrworker_t *w, knot_ns_xfr_t *data)
rcu_read_unlock();
return KNOTD_ERROR;
}
+
+ rcu_read_unlock();
return KNOTD_EOK;
} else {
zd->xfr_in.wrkr = w;
@@ -834,6 +837,7 @@ static int xfr_client_start(xfrworker_t *w, knot_ns_xfr_t *data)
}
if (ret < 0) {
+ rcu_read_unlock();
pthread_mutex_unlock(&zd->xfr_in.lock);
if (fd >= 0) {
close(fd);
@@ -847,6 +851,7 @@ static int xfr_client_start(xfrworker_t *w, knot_ns_xfr_t *data)
/* Duplicate existing socket descriptor. */
data->session = dup(data->session);
if (data->session < 0) {
+ rcu_read_unlock();
pthread_mutex_unlock(&zd->xfr_in.lock);
log_server_warning("Not enough memory to duplicate \n"
"sockets.\n");
@@ -855,7 +860,6 @@ static int xfr_client_start(xfrworker_t *w, knot_ns_xfr_t *data)
}
/* Fetch zone contents. */
- rcu_read_lock();
const knot_zone_contents_t *contents = knot_zone_contents(zone);
if (!contents && data->type == XFR_TYPE_IIN) {
pthread_mutex_unlock(&zd->xfr_in.lock);
--
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