bind/backport-0025-Address-data-race-in-dns_stats_detach-over-reference.patch
jiangheng ad37c37958 backport some patches from community
(cherry picked from commit a9fd9ece9b9436b6103d084920c6897ef1adbae6)
2022-09-03 21:36:21 +08:00

58 lines
1.9 KiB
Diff

From fdb893ede19df7649afd6c6c6ee7e6e666828d10 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Thu, 15 Oct 2020 16:48:24 +1100
Subject: [PATCH] Address data race in dns_stats_detach over references
WARNING: ThreadSanitizer: data race
Write of size 4 at 0x000000000001 by thread T1 (mutexes: write M1):
#0 dns_stats_detach lib/dns/stats.c:115:19
#1 destroy lib/dns/view.c:527:3
#2 dns_view_weakdetach lib/dns/view.c:704:3
#3 zone_free lib/dns/zone.c:1149:3
#4 zone_shutdown lib/dns/zone.c:13123:3
#5 dispatch lib/isc/task.c:1157:7
#6 run lib/isc/task.c:1331:2
Previous read of size 4 at 0x000000000001 by thread T2:
#0 dns_stats_detach lib/dns/stats.c:118:13
#1 destroy lib/dns/view.c:527:3
#2 dns_view_weakdetach lib/dns/view.c:704:3
#3 zone_free lib/dns/zone.c:1152:3
#4 zone_shutdown lib/dns/zone.c:13123:3
#5 dispatch lib/isc/task.c:1157:7
#6 run lib/isc/task.c:1331:2
Conflict: NA
Reference: https://gitlab.isc.org/isc-projects/bind9/-/commit/fdb893ede19df7649afd6c6c6ee7e6e666828d10
---
lib/dns/stats.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/lib/dns/stats.c b/lib/dns/stats.c
index 1473371c64..a0184ecf84 100644
--- a/lib/dns/stats.c
+++ b/lib/dns/stats.c
@@ -104,6 +104,7 @@ dns_stats_attach(dns_stats_t *stats, dns_stats_t **statsp) {
void
dns_stats_detach(dns_stats_t **statsp) {
+ unsigned int references;
dns_stats_t *stats;
REQUIRE(statsp != NULL && DNS_STATS_VALID(*statsp));
@@ -112,10 +113,10 @@ dns_stats_detach(dns_stats_t **statsp) {
*statsp = NULL;
LOCK(&stats->lock);
- stats->references--;
+ references = --stats->references;
UNLOCK(&stats->lock);
- if (stats->references == 0) {
+ if (references == 0) {
isc_stats_detach(&stats->counters);
DESTROYLOCK(&stats->lock);
isc_mem_putanddetach(&stats->mctx, stats, sizeof(*stats));
--
2.23.0