Fix poll() implementation of WaitLatchOrSocket to notice postmaster death.

When the remote end of the pipe is closed, select() reports the fd as
readable, but poll() has a separate POLLHUP return code for that.

Spotted by Peter Geoghegan.

diff --git a/src/backend/port/unix_latch.c b/src/backend/port/unix_latch.c
index fc1a579ad2a94e4768cad38f88f4d41127ba5647..10bf2dbec7ec052cb52d2ff286e46bd5039431d9 100644 (file)
--- a/src/backend/port/unix_latch.c
+++ b/src/backend/port/unix_latch.c
@@ -310,8 +310,13 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
                {
                        result |= WL_SOCKET_WRITEABLE;
                }
+               /*
+                * We expect a POLLHUP when the remote end is closed, but because we
+                * don't expect the pipe to become readable or to have any errors
+                * either, treat those as postmaster death, too.
+                */
                if ((wakeEvents & WL_POSTMASTER_DEATH) &&
-                       (pfds[nfds - 1].revents & POLLIN))
+                       (pfds[nfds - 1].revents & (POLLHUP | POLLIN | POLLERR | POLLNVAL)))
                {
                        result |= WL_POSTMASTER_DEATH;
                }