BUG/MEDIUM: http-ana: Preserve response's FLT_END analyser on L7 retry

When a filter is attached on a stream, the FLT_END analyser must not be
removed from the response channel on L7 retry. It is especially important
because CF_FLT_ANALYZE flag is still set. This means the synchronization
between the two sides when the filter ends can be blocked. Depending on the
timing, this can freeze the stream infinitely or lead to a spinning loop.

Note that the synchronization between the two sides at the end of the
analysis was introduced because the stream was reused in HTTP between two
transactions. But, since the HTX was introduced, a new stream is created for
each transaction. So it is probably possible to remove this step for 2.2 and
higher.

This patch must be backported as far as 2.0.

(cherry picked from commit 7bf46bb9a972c1e9de50b31ce20811f2f59a6849)
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/src/http_ana.c b/src/http_ana.c
index 9c3e68a..715dd3a 100644 (file)
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -1247,7 +1247,7 @@ static __inline int do_l7_retry(struct stream *s, struct stream_interface *si)
        /* Remove any write error from the request, and read error from the response */
        req->flags &= ~(CF_WRITE_ERROR | CF_WRITE_TIMEOUT | CF_SHUTW | CF_SHUTW_NOW);
        res->flags &= ~(CF_READ_ERROR | CF_READ_TIMEOUT | CF_SHUTR | CF_EOI | CF_READ_NULL | CF_SHUTR_NOW);
-       res->analysers = 0;
+       res->analysers &= AN_RES_FLT_END;
        si->flags &= ~(SI_FL_ERR | SI_FL_EXP | SI_FL_RXBLK_SHUT);
        si->err_type = SI_ET_NONE;
        s->flags &= ~(SF_ERR_MASK | SF_FINST_MASK);