From a692a0bd6a8af7427d491adfecff10df3953a8ae Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Wed, 16 Mar 2016 10:44:04 -0700 Subject: [PATCH 1/6] Access the correct pollfd when checking for socket errors in the latch code. Previously, if waiting for a latch, but not a socket, we checked pfds[0].revents for socket errors. Even though pfds[0] wasn't actually associated with the socket in that case. This is currently harmless, because we check wakeEvents after the the aforementioned check. But it's a bug waiting to be happening. --- src/backend/port/unix_latch.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/src/backend/port/unix_latch.c b/src/backend/port/unix_latch.c index 2ad609c..2ffce60 100644 --- a/src/backend/port/unix_latch.c +++ b/src/backend/port/unix_latch.c @@ -365,13 +365,17 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock, /* socket is writable */ result |= WL_SOCKET_WRITEABLE; } - if (pfds[0].revents & (POLLHUP | POLLERR | POLLNVAL)) + if ((wakeEvents & WL_SOCKET_READABLE) && + (pfds[0].revents & (POLLHUP | POLLERR | POLLNVAL))) { - /* EOF/error condition */ - if (wakeEvents & WL_SOCKET_READABLE) - result |= WL_SOCKET_READABLE; - if (wakeEvents & WL_SOCKET_WRITEABLE) - result |= WL_SOCKET_WRITEABLE; + /* EOF/error condition, while waiting for readable socket */ + result |= WL_SOCKET_READABLE; + } + if ((wakeEvents & WL_SOCKET_WRITEABLE) && + (pfds[0].revents & (POLLHUP | POLLERR | POLLNVAL))) + { + /* EOF/error condition, while waiting for writeable socket */ + result |= WL_SOCKET_WRITEABLE; } /* -- 2.7.0.229.g701fa7f