BUG/MEDIUM: connection: Preserve flags when a conn is removed from an idle list
The commit 5e1b0e7bf ("BUG/MEDIUM: connection: Clear flags when a conn is
removed from an idle list") introduced a regression. CO_FL_SAFE_LIST and
CO_FL_IDLE_LIST flags are used when the connection is released to properly
decrement used/idle connection counters. if a connection is idle, these
flags must be preserved till the connection is really released. It may be
removed from the list but not immediately released. If these flags are lost
when it is finally released, the current number of used connections is
erroneously decremented. If means this counter may become negative and the
counters tracking the number of idle connecitons is not decremented,
suggesting a leak.
So, the above commit is reverted and instead we improve a bit the way to
detect an idle connection. The function conn_get_idle_flag() must now be
used to know if a connection is in an idle list. It returns the connection
flag corresponding to the idle list if the connection is idle
(CO_FL_SAFE_LIST or CO_FL_IDLE_LIST) or 0 otherwise. But if the connection
is scheduled to be removed, 0 is also returned, regardless the connection
flags.
This new function is used when the connection is temporarily removed from
the list to be used, mainly in muxes.
This patch should fix #2078 and #2057. It must be backported as far as 2.2.
diff --git a/include/haproxy/connection.h b/include/haproxy/connection.h
index 4d289e7..8cf22ef 100644
--- a/include/haproxy/connection.h
+++ b/include/haproxy/connection.h
@@ -316,6 +316,16 @@
}
}
+/* Used to know if a connection is in an idle list. It returns connection flag
+ * corresponding to the idle list if the connection is idle (CO_FL_SAFE_LIST or
+ * CO_FL_IDLE_LIST) or 0 otherwise. Note that if the connection is scheduled to
+ * be removed, 0 is returned, regardless the connection flags.
+ */
+static inline unsigned int conn_get_idle_flag(const struct connection *conn)
+{
+ return (!MT_LIST_INLIST(&conn->toremove_list) ? conn->flags & CO_FL_LIST_MASK : 0);
+}
+
static inline void conn_force_unsubscribe(struct connection *conn)
{
if (!conn->subs)
diff --git a/src/connection.c b/src/connection.c
index 97619ec..29197ad 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -146,7 +146,7 @@
((conn->flags ^ old_flags) & CO_FL_NOTIFY_DONE) ||
((old_flags & CO_FL_WAIT_XPRT) && !(conn->flags & CO_FL_WAIT_XPRT))) &&
conn->mux && conn->mux->wake) {
- uint conn_in_list = conn->flags & CO_FL_LIST_MASK;
+ uint conn_in_list = conn_get_idle_flag(conn);
struct server *srv = objt_server(conn->target);
if (conn_in_list) {
diff --git a/src/mux_fcgi.c b/src/mux_fcgi.c
index fd74b56..0fb4f86 100644
--- a/src/mux_fcgi.c
+++ b/src/mux_fcgi.c
@@ -2957,7 +2957,7 @@
conn = fconn->conn;
TRACE_POINT(FCGI_EV_FCONN_WAKE, conn);
- conn_in_list = conn->flags & CO_FL_LIST_MASK;
+ conn_in_list = conn_get_idle_flag(conn);
if (conn_in_list)
conn_delete_from_tree(&conn->hash_node->node);
@@ -3140,10 +3140,8 @@
/* We're about to destroy the connection, so make sure nobody attempts
* to steal it from us.
*/
- if (fconn->conn->flags & CO_FL_LIST_MASK) {
+ if (fconn->conn->flags & CO_FL_LIST_MASK)
conn_delete_from_tree(&fconn->conn->hash_node->node);
- fconn->conn->flags &= ~CO_FL_LIST_MASK;
- }
HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
}
diff --git a/src/mux_h1.c b/src/mux_h1.c
index 2390aad..5b00b1b 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -3186,7 +3186,7 @@
/* Remove the connection from the list, to be sure nobody attempts
* to use it while we handle the I/O events
*/
- conn_in_list = conn->flags & CO_FL_LIST_MASK;
+ conn_in_list = conn_get_idle_flag(conn);
if (conn_in_list)
conn_delete_from_tree(&conn->hash_node->node);
@@ -3309,10 +3309,8 @@
/* We're about to destroy the connection, so make sure nobody attempts
* to steal it from us.
*/
- if (h1c->conn->flags & CO_FL_LIST_MASK) {
+ if (h1c->conn->flags & CO_FL_LIST_MASK)
conn_delete_from_tree(&h1c->conn->hash_node->node);
- h1c->conn->flags &= ~CO_FL_LIST_MASK;
- }
HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
}
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 293c414..4b42639 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -3895,11 +3895,10 @@
conn = h2c->conn;
TRACE_ENTER(H2_EV_H2C_WAKE, conn);
- conn_in_list = conn->flags & CO_FL_LIST_MASK;
-
/* Remove the connection from the list, to be sure nobody attempts
* to use it while we handle the I/O events
*/
+ conn_in_list = conn_get_idle_flag(conn);
if (conn_in_list)
conn_delete_from_tree(&conn->hash_node->node);
@@ -4031,7 +4030,6 @@
if (conn->flags & CO_FL_LIST_MASK) {
HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
conn_delete_from_tree(&conn->hash_node->node);
- conn->flags &= ~CO_FL_LIST_MASK;
HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
}
}
@@ -4040,7 +4038,6 @@
if (conn->flags & CO_FL_LIST_MASK) {
HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
conn_delete_from_tree(&conn->hash_node->node);
- conn->flags &= ~CO_FL_LIST_MASK;
HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
}
}
@@ -4120,10 +4117,8 @@
/* We're about to destroy the connection, so make sure nobody attempts
* to steal it from us.
*/
- if (h2c->conn->flags & CO_FL_LIST_MASK) {
+ if (h2c->conn->flags & CO_FL_LIST_MASK)
conn_delete_from_tree(&h2c->conn->hash_node->node);
- h2c->conn->flags &= ~CO_FL_LIST_MASK;
- }
HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
}
@@ -4176,7 +4171,6 @@
if (h2c->conn->flags & CO_FL_LIST_MASK) {
HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
conn_delete_from_tree(&h2c->conn->hash_node->node);
- h2c->conn->flags &= ~CO_FL_LIST_MASK;
HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
}
diff --git a/src/server.c b/src/server.c
index 45fc33f..ade6aaf 100644
--- a/src/server.c
+++ b/src/server.c
@@ -5828,7 +5828,6 @@
hash_node = ebmb_entry(node, struct conn_hash_node, node);
eb_delete(node);
- hash_node->conn->flags &= ~CO_FL_LIST_MASK;
MT_LIST_APPEND(toremove_list, &hash_node->conn->toremove_list);
i++;
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index fc9de55..fa080d6 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -6197,7 +6197,7 @@
return NULL;
}
conn = ctx->conn;
- conn_in_list = conn->flags & CO_FL_LIST_MASK;
+ conn_in_list = conn_get_idle_flag(conn);
if (conn_in_list)
conn_delete_from_tree(&conn->hash_node->node);
HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);