From: Mark Andrews <marka@isc.org>
Date: Tue, 8 Aug 2017 23:51:59 +0000 (+1000)
Subject: add comment
X-Git-Tag: v9.12.0a1~131^2~6
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=31605091b40fda47d34128ce74499b8565ad8f87;p=thirdparty%2Fbind9.git

add comment
---

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index a00c395db66..8d3df4ecc75 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -6653,6 +6653,14 @@ resume_dslookup(isc_task_t *task, isc_event_t *event) {
 	dns_rdataset_init(&nameservers);
 
 	bucketnum = fctx->bucketnum;
+
+	/*
+	 * Note: fevent->rdataset must be disassociated and
+	 * isc_event_free(&event) be called before resuming
+	 * processing of the 'fctx' to prevent use-after-free.
+	 * 'fevent' is set to NULL so as to not have a dangling
+	 * pointer.
+	 */
 	if (fevent->result == ISC_R_CANCELED) {
 		if (dns_rdataset_isassociated(fevent->rdataset)) {
 			dns_rdataset_disassociate(fevent->rdataset);