[compiler-rt] r226913 - [sanitizer] Fix an edge case in MemoryRangeIsAvailable.

[Alexey Samsonov]

On Fri, Jan 23, 2015 at 7:14 AM, Evgeniy Stepanov <eugeni.stepanov at gmail.com
> wrote:

> Author: eugenis
> Date: Fri Jan 23 09:14:27 2015
> New Revision: 226913
>
> URL: http://llvm.org/viewvc/llvm-project?rev=226913&view=rev
> Log:
> [sanitizer] Fix an edge case in MemoryRangeIsAvailable.
>
> Modified:
>     compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
>
> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
> URL:
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc?rev=226913&r1=226912&r2=226913&view=diff
>
> ==============================================================================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc Fri Jan 23
> 09:14:27 2015
> @@ -237,7 +237,8 @@ bool MemoryRangeIsAvailable(uptr range_s
>    while (proc_maps.Next(&start, &end,
>                          /*offset*/0, /*filename*/0, /*filename_size*/0,
>                          /*protection*/0)) {
> -    if (!IntervalsAreSeparate(start, end, range_start, range_end))
> +    CHECK_NE(0, end);
> +    if (!IntervalsAreSeparate(start, end - 1, range_start, range_end))
>        return false;
>    }
>

I don't believe this is the correct fix. IntervalsAreSeparate should treat
its arguments as [start1, end1) and [start2, end2), and
therefore check that (end1 <= start2) || (end2 <= start1);

Otherwise, your change should also subtract one from range_end.


>    return true;
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>



-- 
Alexey Samsonov
vonosmas at gmail.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150127/5724980b/attachment.html>