From: Evan Hunt <each@isc.org>
Date: Tue, 6 Sep 2022 21:13:23 +0000 (-0700)
Subject: prevent a possible shutdown hang in rndc
X-Git-Tag: v9.19.6~68^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9683439d7399e1e525853c42f7cc337b3081405e;p=thirdparty%2Fbind9.git

prevent a possible shutdown hang in rndc

In rndc_recvdone(), if 'sends' was not 0, then 'recvs' was not
decremented, in which case isc_loopmgr_shutdown() was never reached,
which could cause a hang. (This has not been observed to happen, but
the code was incorrect on examination.)
---

diff --git a/bin/rndc/rndc.c b/bin/rndc/rndc.c
index cabeb91e055..ff7b9e8e551 100644
--- a/bin/rndc/rndc.c
+++ b/bin/rndc/rndc.c
@@ -390,8 +390,8 @@ rndc_recvdone(isc_nmhandle_t *handle, isc_result_t result, void *arg) {
 	REQUIRE(recvdone_handle == handle);
 	isc_nmhandle_detach(&recvdone_handle);
 
-	if (atomic_load_acquire(&sends) == 0 &&
-	    atomic_fetch_sub_release(&recvs, 1) == 1)
+	if (atomic_fetch_sub_release(&recvs, 1) == 1 &&
+	    atomic_load_acquire(&sends) == 0)
 	{
 		shuttingdown = true;
 		isc_task_detach(&rndc_task);