gdbstub: set listen backlog to 1
Avoid possible connection drops on Linux (when tcp_syncookies is
disabled) or fallbacks to SYN cookies with the following kernel warning:
TCP: request_sock_TCP: Possible SYN flooding on port 1234. Sending cookies. Check SNMP counters.
Since Linux 4.4 (ef547f2ac16b "tcp: remove max_qlen_log"), a backlog of
zero is really treated as the "queue length for completely established
sockets waiting to be accepted" (listen(2)). This is apparently a valid
interpretation of an "implementation-defined minimum value" for a
backlog value of 0 (listen(3p)). Previous kernels would use 8 as
minimum value, but that is no longer the case.
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/gdbstub.c b/gdbstub.c
index 8155eed..9d39513 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1631,7 +1631,7 @@
close(fd);
return -1;
}
- ret = listen(fd, 0);
+ ret = listen(fd, 1);
if (ret < 0) {
perror("listen");
close(fd);
