Date: Fri, 21 Oct 2005 16:37:22 +0100
From: Alex Bligh - linux-kernel <linux-kernel@alex.org.uk>
Reply-To: Alex Bligh - linux-kernel <linux-kernel@alex.org.uk>
To: Arjan van de Ven <arjan@infradead.org>,
       "Vincent W. Freeh" <vin@csc.ncsu.edu>
Cc: linux-kernel@vger.kernel.org,
       Alex Bligh - linux-kernel <linux-kernel@alex.org.uk>
Subject: Re: Understanding Linux addr space, malloc, and heap
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--On 21 October 2005 17:22 +0200 Arjan van de Ven <arjan@infradead.org> 
wrote:

> Ok I meant in the "while adhering to the standard" :)

More precisely, as per the man page:
> POSIX.1b says that mprotect can be used only on regions of memory
> obtained from mmap(2).

But what is interesting (if anything) is this:
> ERRORS
>        EINVAL addr is not a valid pointer, or not a  multiple  of
>        PAGESIZE.

So if he calls mprotect with memory allocated by malloc (which should
fail), why doesn't he get EINVAL? He says it returns 0 (meaning it
succeeded). Which it shouldn't (unless he is stupendously lucky in
malloc's allocation, in which case it should work).

--
Alex Bligh
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