tree dbbef09b7604b7aa9e859d1ca081d7bb24ddedf4
parent a429ad3fb0261bbe7ae0bc1cc247e4236739828f
author Christopher Faulet <cfaulet@haproxy.com> 1622549165 +0200
committer Christopher Faulet <cfaulet@haproxy.com> 1623329256 +0200

BUG/MAJOR: stream-int: Release SI endpoint on server side ASAP on retry

When a connection attempt failed, if a retry is possible, the SI endpoint on
the server side is immediately released, instead of waiting to establish a
new connection to a server. Thus, when the backend SI is switched from
SI_ST_CER state to SI_ST_REQ, SI_ST_ASS or SI_ST_TAR, its endpoint is
released. It is expected because the SI is moved to a state prior to the
connection stage ( < SI_ST_CONN). So it seems logical to not have any server
connection.

It is especially important if the retry is delayed (SI_ST_TAR or
SI_ST_QUE). Because, if the server connection is preserved, any error at the
connection level is unexpectedly relayed to the stream, via the
stream-interface, leading to an infinite loop in process_stream(). if
SI_FL_ERR flag is set on the backend SI in another state than SI_ST_CLO, an
internal goto is performed to resync the stream-interfaces. In addtition,
some ressources are not released ASAP.

This bug is quite old and was reported 1 or 2 times per years since the 2.2
(at least) with not enough information to catch it. It must be backported as
far as 2.2 with a special care because this part has moved several times and
after some observation period and feedback from users to be sure. For info,
in 2.0 and prior, the connection is released when an error is encountered in
SI_ST_CON or SI_ST_RDY states.

(cherry picked from commit f822decfda1f662147c02fd8b4f752da7500f374)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>