KNOWN_BUGS: wakeup socket disconnect causes havoc

Closes #6132
Closes #6133

docs/KNOWN_BUGS

@@ -107,6 +107,7 @@ problems may have been fixed or changed somewhat since this was written!
  11.10 Blocking socket operations in non-blocking API
  11.11 A shared connection cache is not thread-safe
  11.12 'no_proxy' string-matches IPv6 numerical addresses
+ 11.13 wakeup socket disconnect causes havoc
 
  12. LDAP
  12.1 OpenLDAP hangs after returning results
@@ -785,6 +786,18 @@ problems may have been fixed or changed somewhat since this was written!
 
  See https://github.com/curl/curl/issues/5745
 
+11.13 wakeup socket disconnect causes havoc
+
+ waking an iPad breaks the wakeup socket pair, triggering a POLLIN event and
+ resulting in SOCKERRNO being set to ENOTCONN.
+
+ This condition, and other possible error conditions on the wakeup socket, are
+ not handled, so the condition remains on the FD and curl_multi_poll will
+ never block again.
+
+ See https://github.com/curl/curl/issues/6132 and
+ https://github.com/curl/curl/pull/6133
+
 12. LDAP
 
 12.1 OpenLDAP hangs after returning results