| Message ID | 1462354337-1733-1-git-send-email-peter@lekensteyn.nl (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
04.05.2016 12:32, Peter Wu wrote: > 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. Applied to -trivial, thanks! /mjt
diff --git a/gdbstub.c b/gdbstub.c index b126bf5..f181dc3 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -1630,7 +1630,7 @@ static int gdbserver_open(int port) close(fd); return -1; } - ret = listen(fd, 0); + ret = listen(fd, 1); if (ret < 0) { perror("listen"); close(fd);
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> --- Hi, This was also reported at Linux, but the author of that patch argued that it is intended behavior[1]. Kind regards, Peter [1]: https://lkml.kernel.org/r/1462321544.5535.337.camel@edumazet-glaptop3.roam.corp.google.com --- gdbstub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)