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Date: Tue, 12 Jan 2016 15:25:57 +0300
From: Alexander Cherepanov <ch3root@...nwall.com>
To: musl@...ts.openwall.com
Subject: Re: Possible infinite loop in qsort()

On 2016-01-10 14:38, Markus Wichmann wrote:
> On Sat, Jan 09, 2016 at 11:05:16PM -0500, Rich Felker wrote:
>> On Sat, Jan 09, 2016 at 10:07:19AM +0100, Felix Janda wrote:
>>> musl enforces that object sizes should not be greater than PTRDIFF_MAX.
>>> See for example the discussion at
>>>
>>> http://www.openwall.com/lists/musl/2013/06/27/7
>>>
>>> So there will not be objects of size 3GB with musl on x32. Since the
>>> Leonardo numbers grow slower than 2^n in general no overflow should
>>> happen if "size" is valid. Otherwise, UB was invoked.
>>
>
> OK. Might want to make that assumption a bit more prominent, because
> this is the first time I've ever heard about it, but OK, no objects >2GB
> on 32-bit archs.

Yeah, I don't see it in the doc. Did I miss it?

If it neither works nor documented as a limit I'd call it a bug.

BTW the support in compilers for working with objects larger than half 
the address space is buggy -- see 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67999 . The same situation 
-- it neither works nor documented. Somewhat puzzling...

-- 
Alexander Cherepanov

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