From: Evan Hunt <each@isc.org>
Date: Mon, 9 Nov 2020 20:33:37 +0000 (-0800)
Subject: address some possible shutdown races in xfrin
X-Git-Tag: v9.17.7~15^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e011521ef163779a8ec885ab630cb694a446e95e;p=thirdparty%2Fbind9.git

address some possible shutdown races in xfrin

there were two failures during observed in testing, both occurring
when 'rndc halt' was run rather than 'rndc stop' - the latter dumps
zone contents to disk and presumably introduced enough delay to
prevent the races:

- a failure when the zone was shut down and called dns_xfrin_detach()
  before the xfrin had finished connecting; the connect timeout
  terminated without detaching its handle
- a failure when the tcpdns socket timer fired after the outerhandle
  had already been cleared.

this commit incidentally addresses a failure observed in mutexatomic
due to a variable having been initialized incorrectly.
---

diff --git a/bin/named/server.c b/bin/named/server.c
index be731815bac..af3ea264420 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -10004,7 +10004,7 @@ named_server_create(isc_mem_t *mctx, named_server_t **serverp) {
 				     &server->in_roothints),
 		   "setting up root hints");
 
-	atomic_store(&server->reload_status, NAMED_RELOAD_IN_PROGRESS);
+	atomic_init(&server->reload_status, NAMED_RELOAD_IN_PROGRESS);
 
 	/*
 	 * Setup the server task, which is responsible for coordinating
diff --git a/lib/dns/xfrin.c b/lib/dns/xfrin.c
index 497318472ce..71a5eab2efd 100644
--- a/lib/dns/xfrin.c
+++ b/lib/dns/xfrin.c
@@ -937,7 +937,7 @@ xfrin_connect_done(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
 			TIME_NOW(&now);
 			dns_zonemgr_unreachableadd(zmgr, &xfr->masteraddr,
 						   &xfr->sourceaddr, &now);
-			goto failure;
+			CHECK(result);
 		} else {
 			dns_zonemgr_unreachabledel(zmgr, &xfr->masteraddr,
 						   &xfr->sourceaddr);
@@ -959,9 +959,10 @@ xfrin_connect_done(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
 		  signer);
 
 	CHECK(xfrin_send_request(xfr));
-	isc_nmhandle_detach(&handle);
 
 failure:
+	isc_nmhandle_detach(&handle);
+
 	if (result != ISC_R_SUCCESS && result != ISC_R_SHUTTINGDOWN) {
 		xfrin_fail(xfr, result, "failed to connect");
 	}
diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index b06d56415da..aa2003ea795 100644
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -98,7 +98,9 @@ dnstcp_readtimeout(uv_timer_t *timer) {
 	REQUIRE(sock->tid == isc_nm_tid());
 
 	/* Close the TCP connection; its closure should fire ours. */
-	isc_nmhandle_detach(&sock->outerhandle);
+	if (sock->outerhandle != NULL) {
+		isc_nmhandle_detach(&sock->outerhandle);
+	}
 }
 
 /*