BUG/MEDIUM: stream-int: don't subscribed for recv when we're trying to flush data
If we cannot splice incoming data using rcv_pipe() due to remaining data
in the buffer, we must not subscribe to the mux but instead tag the
stream-int as blocked on missing Rx room. Otherwise when data are
flushed, calling si_chk_rcv() will have no effect because the WAIT_EP
flag remains present, and we'll end in an rx timeout. This case is very
hard to reproduce, and requires an inversion of the polling side in the
middle of a transfer. This can only happen when the client and the server
are using similar links and when splicing is enabled. It typically takes
hundreds of MB to GB for the problem to happen, and tends to be magnified
by the use of option contstats which causes process_stream() to be called
every 5s and to try again to recv.
This fix must be backported to 2.1, 2.0, and possibly 1.9.
(cherry picked from commit 1ac5f208042ff571c9341aed0380ca52c084a261)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit c4fcb6b3644b87a46fb8735a387b9bd9bf61ffaf)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/src/stream_interface.c b/src/stream_interface.c
index e37d0b9..0669546 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -1360,6 +1360,13 @@
}
if (ret <= 0) {
+ /* if we refrained from reading because we asked for a
+ * flush to satisfy rcv_pipe(), we must not subscribe
+ * and instead report that there's not enough room
+ * here to proceed.
+ */
+ if (flags & CO_RFL_BUF_FLUSH)
+ si_rx_room_blk(si);
break;
}