From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Tue, 1 Jun 2021 14:26:04 +0000 (+0200)
Subject: daemon/worker: fix a memory leak
X-Git-Tag: v5.4.0~13^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5b2ba2d21dd844771586f96d496335ec037dbf1c;p=thirdparty%2Fknot-resolver.git

daemon/worker: fix a memory leak

Discovered case: TCP write towards upstream fails due to ECONNRESET,
and on this place of code we "forget" the whole qr_task and thus its
corresponding kr_request, so it remains unanswered and using memory.
---

diff --git a/NEWS b/NEWS
index 8924e548a..ec47b974c 100644
--- a/NEWS
+++ b/NEWS
@@ -8,6 +8,7 @@ Improvements
 Bugfixes
 --------
 - trust_anchors.set_insecure: improve precision (#673, !1177)
+- plug memory leaks related to TCP (!1182)
 
 Incompatible changes
 --------------------
diff --git a/daemon/worker.c b/daemon/worker.c
index f1ade4d25..b97a66c26 100644
--- a/daemon/worker.c
+++ b/daemon/worker.c
@@ -633,8 +633,22 @@ int qr_task_on_send(struct qr_task *task, const uv_handle_t *handle, int status)
 	}
 
 	if (handle->type == UV_TCP) {
-		if (status != 0)
-			session_tasklist_del(s, task);
+		if (status != 0) { // session probably not usable anymore; typically: ECONNRESET
+			if (VERBOSE_STATUS) {
+				const char *peer_str = NULL;
+				if (!session_flags(s)->outgoing) {
+					peer_str = "hidden"; // avoid logging downstream IPs
+				} else if (task->transport) {
+					peer_str = kr_straddr(&task->transport->address.ip);
+				}
+				if (!peer_str)
+					peer_str = "unknown"; // probably shouldn't happen
+				kr_log_verbose( "[wrkr]=> disconnected from '%s': %s\n",
+						peer_str, uv_strerror(status));
+			}
+			worker_end_tcp(s);
+			return status;
+		}
 
 		if (session_flags(s)->outgoing || session_flags(s)->closing)
 			return status;