From: Evan Hunt <each@isc.org>
Date: Thu, 11 Aug 2022 22:06:34 +0000 (-0700)
Subject: Lock the address entry bucket when dumping ADB namehook
X-Git-Tag: v9.19.5~41^2
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=e79be4bd8a5e4b390ccb0e875b5e213e727c58bb;p=thirdparty%2Fbind9.git

Lock the address entry bucket when dumping ADB namehook

When dumping an ADB address entry associated with a name,
the name bucket lock was held, but the entry bucket lock was
not; this could cause data races when other threads were updating
address entry info. (These races are probably not operationally
harmful, but they triggered TSAN error reports.)
---

diff --git a/lib/dns/adb.c b/lib/dns/adb.c
index 3ff149a7740..bca098f016e 100644
--- a/lib/dns/adb.c
+++ b/lib/dns/adb.c
@@ -2946,7 +2946,9 @@ print_namehook_list(FILE *f, const char *legend, dns_adb_t *adb,
 		if (debug) {
 			fprintf(f, ";\tHook(%s) %p\n", legend, nh);
 		}
+		LOCK(&nh->entry->bucket->lock);
 		dump_entry(f, adb, nh->entry, debug, now);
+		UNLOCK(&nh->entry->bucket->lock);
 	}
 }