BUG/MEDIUM: checks: Make sure we set the task affinity just before connecting.
In process_chk_conn(), make sure we set the task affinity to the current
thread as soon as we're attempting a connection (and reset the affinity to
"any thread" if we detect a failure).
We used to only set the task affinity if connect_conn_chk() returned
SF_ERR_NONE, however for TCP checks, SF_ERR_UP is returned, so for those
checks, the task could still run on any thread, and this could lead to a
race condition where the connection runs on one thread, while the task runs
on another one, which could create random memory corruption and/or crashes.
This may fix github issue #369.
This should be backported to 2.1, 2.0 and 1.9.
diff --git a/src/checks.c b/src/checks.c
index 909bd52..aa93bab 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -2245,6 +2245,7 @@
b_reset(&check->bi);
b_reset(&check->bo);
+ task_set_affinity(t, tid_bit);
ret = connect_conn_chk(t);
cs = check->cs;
conn = cs_conn(cs);
@@ -2276,7 +2277,6 @@
__event_srv_chk_r(cs);
}
- task_set_affinity(t, tid_bit);
goto reschedule;
case SF_ERR_SRVTO: /* ETIMEDOUT */
@@ -2298,6 +2298,7 @@
}
/* here, we have seen a synchronous error, no fd was allocated */
+ task_set_affinity(t, MAX_THREADS_MASK);
if (cs) {
if (check->wait_list.events)
cs->conn->xprt->unsubscribe(cs->conn,