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[Bug libc/4714] bus error when trying to access page created by mremap()
- From: "tambewilliam at gmail dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: 2 Jul 2007 02:43:39 -0000
- Subject: [Bug libc/4714] bus error when trying to access page created by mremap()
- References: <20070629183244.4714.tambewilliam@gmail.com>
- Reply-to: sourceware-bugzilla at sourceware dot org
------- Additional Comments From tambewilliam at gmail dot com 2007-07-02 02:43 -------
Subject: Re: New: bus error when trying to access page created
by mremap()
I don't mean to press anybody, but please, can somebody help to find a
work around if there is not immediate solutions.
Sincerely,
William Tambe
tambewilliam at gmail dot com wrote:
> In the code below, I mmap() a single page of 4096 and simply mremap() the same
> page to 2*4096 which is 8192.
>
> Then when I try to write anywhere after 4096 bytes, in the newly expanded area.
> I get Bus error.
>
> Can somebody please help me?
>
>
> #define _GNU_SOURCE
> #include <sys/mman.h>
> #include <unistd.h>
>
> #include <stdio.h>
>
> main() {
> void *ptr;
> if ((ptr=mmap(0, 4096, PROT_READ|PROT_WRITE,
> MAP_ANONYMOUS|MAP_SHARED|MAP_GROWSDOWN, 0, 0)) == -1) {
> printf("failed to mmap\n");
> return;
> }
>
> if ((ptr=mremap(ptr, 4096, 8192, MREMAP_MAYMOVE)) == -1) {
> printf("failed to mremap\n");
> return;
> }
>
> //why does this failed. I am well in the interval [4096, 8192]
> *(unsigned int *)(ptr + 4096 + 8)= 10;
> }
>
--
http://sourceware.org/bugzilla/show_bug.cgi?id=4714
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