1 files changed, 23 insertions, 1 deletions

diff --git a/src/net.cpp b/src/net.cpp
index 964097b..77f9acf 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -1471,11 +1471,29 @@ void ThreadSocketHandler2(void* parg)
 #else
                     socklen_t nTypeLen = sizeof(nType);
 #endif
-                    if (getsockopt(pnode->hSocket, SOL_SOCKET, SO_TYPE, (char*)&nType, &nTypeLen) != 0)
+                    if (pnode->hSocket != INVALID_SOCKET &&
+                        getsockopt(pnode->hSocket, SOL_SOCKET, SO_TYPE, (char*)&nType, &nTypeLen) != 0)
                     {
                         printf("dropping node %s: its socket is no longer valid\n",
                                pnode->addr.ToString().c_str());
                         pnode->fDisconnect = true;
+
+                        // Stop referring to it, or it goes back into the next
+                        // select() set and fails it again.
+                        //
+                        // Marking fDisconnect is not enough: a node is only
+                        // removed from vNodes once it has drained or once
+                        // DISCONNECT_DRAIN_SECS has passed, so one dead
+                        // descriptor kept failing select() for a full minute --
+                        // and a failed select() zeroes both sets above, which
+                        // means NO peer is read on that pass. Measured on a
+                        // wedged pool: 1,027 consecutive passes over 61
+                        // seconds, one bad socket, the entire node deaf.
+                        //
+                        // Not closed, only forgotten. getsockopt just told us
+                        // this descriptor is not ours any more; closing it now
+                        // is how an unrelated socket gets closed instead.
+                        pnode->hSocket = INVALID_SOCKET;
                     }
                 }
             }
@@ -1548,6 +1566,10 @@ void ThreadSocketHandler2(void* parg)
         {
             CheckForShutdown(0);
             SOCKET hSocket = pnode->hSocket;
+            // Forgotten above because it was already invalid. FD_ISSET on it
+            // is meaningless and recv()/send() would be operating on -1.
+            if (hSocket == INVALID_SOCKET)
+                continue;
 
             //
             // Receive