BUG/MEDIUM: proto_udp/threads: recv() and send() must not be exclusive.

This is a complement to previous fix for bug #399. The exclusion between
the recv() and send() calls prevents send handlers from being called if
rx readiness is reported. The DNS code can trigger this situations with
threads where the fd_recv_ready() flag disappears between the test in
dgram_fd_handler() and the second test in dns_resolve_recv() while a
thread calls fd_cant_recv(), and this situation can sustain itself for
a while. With 8 threads and an error in the socket queue, placing a
printf on the return statement in dns_resolve_recv() scrolls very fast.

Simply removing the "else" in dgram_fd_handler() addresses the issue.

This fix must be backported as far as 1.6.

diff --git a/src/proto_udp.c b/src/proto_udp.c
index c4434d78eaa6aa627890f59918d72a41a674aff2..810c31416ddd6593ce38848a97c93cadf9dc60d9 100644 (file)
--- a/src/proto_udp.c
+++ b/src/proto_udp.c
@@ -26,7 +26,7 @@ void dgram_fd_handler(int fd)
 
        if (fd_recv_ready(fd))
                dgram->data->recv(dgram);
-       else if (fd_send_ready(fd))
+       if (fd_send_ready(fd))
                dgram->data->send(dgram);
 
        return;