From: Ian Lance Taylor <ian@gcc.gnu.org>
Date: Thu, 26 Nov 2015 00:24:21 +0000 (+0000)
Subject: re PR go/61303 (gccgo: segfault, regression since 4.8.2)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ae026741df1a3f1dfe86ffde544010027a4c08b1;p=gcc.git

re PR go/61303 (gccgo: segfault, regression since 4.8.2)

	PR go/61303
    runtime: don't overallocate in select code

    If we've already allocated an fd_set, don't allocate another one.

    Also, don't bother to read from rdwake if it wasn't returned in select.

    Fixes https://gcc.gnu.org/PR61303.

    Reviewed-on: https://go-review.googlesource.com/17243

From-SVN: r230922
---

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 9fe9d5e1042..80136abcf76 100644
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-0d979f0b860cfd879754150e0ae5e1018b94d7c4
+81eb6a3f425b2158c67ee32c0cc973a72ce9d6be
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
diff --git a/libgo/runtime/netpoll_select.c b/libgo/runtime/netpoll_select.c
index b4613359118..033661d17f2 100644
--- a/libgo/runtime/netpoll_select.c
+++ b/libgo/runtime/netpoll_select.c
@@ -135,6 +135,8 @@ runtime_netpoll(bool block)
 	byte b;
 	struct stat st;
 
+	allocatedfds = false;
+
  retry:
 	runtime_lock(&selectlock);
 
@@ -146,11 +148,13 @@ runtime_netpoll(bool block)
 	}
 
 	if(inuse) {
-		prfds = runtime_SysAlloc(4 * sizeof fds, &mstats.other_sys);
-		pwfds = prfds + 1;
-		pefds = pwfds + 1;
-		ptfds = pefds + 1;
-		allocatedfds = true;
+		if(!allocatedfds) {
+			prfds = runtime_SysAlloc(4 * sizeof fds, &mstats.other_sys);
+			pwfds = prfds + 1;
+			pefds = pwfds + 1;
+			ptfds = pefds + 1;
+			allocatedfds = true;
+		}
 	} else {
 		prfds = &grfds;
 		pwfds = &gwfds;
@@ -216,7 +220,7 @@ runtime_netpoll(bool block)
 			mode = 'r' + 'w';
 			--c;
 		}
-		if(i == rdwake) {
+		if(i == rdwake && mode != 0) {
 			while(read(rdwake, &b, sizeof b) > 0)
 				;
 			continue;