diff options
| author | Dmitriy Vyukov <dvyukov@google.com> | 2011-07-12 01:21:06 -0400 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2011-07-12 01:21:06 -0400 |
| commit | f9f21aa1fb45aaa4eece55f192783bfa46df4909 (patch) | |
| tree | d9733196177d563754392a1cf4a62e4ea4167585 /src | |
| parent | 8ed9fc600c7dc6a9286a6f04bdb41694d53bac3c (diff) | |
| download | go-f9f21aa1fb45aaa4eece55f192783bfa46df4909.tar.xz | |
runtime: fix data race on runtime·maxstring
The data race can lead to erroneous output of
"[invalid string]" instead of a string.
R=golang-dev
CC=golang-dev
https://golang.org/cl/4678049
Diffstat (limited to 'src')
| -rw-r--r-- | src/pkg/runtime/print.c | 2 | ||||
| -rw-r--r-- | 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; } |