From f9f21aa1fb45aaa4eece55f192783bfa46df4909 Mon Sep 17 00:00:00 2001 From: Dmitriy Vyukov Date: Tue, 12 Jul 2011 01:21:06 -0400 Subject: [PATCH] =?utf8?q?runtime:=20fix=20data=20race=20on=20runtime?= =?utf8?q?=C2=B7maxstring=20The=20data=20race=20can=20lead=20to=20erroneou?= =?utf8?q?s=20output=20of=20"[invalid=20string]"=20instead=20of=20a=20stri?= =?utf8?q?ng.?= MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit R=golang-dev CC=golang-dev https://golang.org/cl/4678049 --- src/pkg/runtime/print.c | 2 +- src/pkg/runtime/string.goc | 10 +++++++--- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/src/pkg/runtime/print.c b/src/pkg/runtime/print.c index b8069aa393..3ce7794957 100644 --- a/src/pkg/runtime/print.c +++ b/src/pkg/runtime/print.c @@ -320,7 +320,7 @@ runtime·printpointer(void *p) void runtime·printstring(String v) { - extern int32 runtime·maxstring; + extern uint32 runtime·maxstring; if(v.len > runtime·maxstring) { runtime·write(2, "[invalid string]", 16); diff --git a/src/pkg/runtime/string.goc b/src/pkg/runtime/string.goc index b72aa937c3..15b3459ada 100644 --- a/src/pkg/runtime/string.goc +++ b/src/pkg/runtime/string.goc @@ -32,19 +32,23 @@ runtime·findnullw(uint16 *s) return l; } -int32 runtime·maxstring = 256; +uint32 runtime·maxstring = 256; String runtime·gostringsize(int32 l) { String s; + uint32 ms; if(l == 0) return runtime·emptystring; s.str = runtime·mal(l+1); // leave room for NUL for C runtime (e.g., callers of getenv) s.len = l; - if(l > runtime·maxstring) - runtime·maxstring = l; + for(;;) { + ms = runtime·maxstring; + if((uint32)l <= ms || runtime·cas(&runtime·maxstring, ms, (uint32)l)) + break; + } return s; } -- 2.50.0