code review 8550043: runtime: fix integer overflow in hashmap

runtime: fix integer overflow in hashmap
The test is problematic, because it requires 8GB+ of RAM.
Fixes issue 5239.

[dvyukov, 2013-04-09 01:38:52]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go/

[bradfitz, 2013-04-09 01:39:56]

LGTM

Thanks!



On Mon, Apr 8, 2013 at 6:38 PM, <dvyukov@google.com> wrote:

> Reviewers: golang-dev1,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
>
https://dvyukov%40google.com@**code.google.com/p/go/<http://40google.com@code...
>
>
> Description:
> runtime: fix integer overflow in hashmap
> The test is problematic, because it requires 8GB+ of RAM.
> Fixes issue 5239.
>
> Please review this at
https://codereview.appspot.**com/8550043/<https://codereview.appspot.com/8550...
>
> Affected files:
>   M src/pkg/runtime/hashmap.c
>
>
> Index: src/pkg/runtime/hashmap.c
> ==============================**==============================**=======
> --- a/src/pkg/runtime/hashmap.c
> +++ b/src/pkg/runtime/hashmap.c
> @@ -451,7 +451,7 @@
>         old_buckets = h->buckets;
>         // NOTE: this could be a big malloc, but since we don't need
> zeroing it is probably fast.
>         if(checkgc) mstats.next_gc = mstats.heap_alloc;
> -       new_buckets = runtime·mallocgc(h->bucketsize << (h->B + 1), 0, 1,
> 0);
> +       new_buckets = runtime·mallocgc((uintptr)h->**bucketsize << (h->B
> + 1), 0, 1, 0);
>         flags = (h->flags & ~(Iterator | OldIterator));
>         if((h->flags & Iterator) != 0) {
>                 flags |= OldIterator;
>
>
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>

[dvyukov, 2013-04-09 01:56:45]

*** Submitted as https://code.google.com/p/go/source/detail?r=6b6253f60ef9 ***

runtime: fix integer overflow in hashmap
The test is problematic, because it requires 8GB+ of RAM.
Fixes issue 5239.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/8550043