linux-kernel - Concerning a post that you made about expandable anonymous shared mappings

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 29 Jun 2007 14:52:22 -0500
From:	William Tambe <tambewilliam@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Concerning a post that you made about expandable anonymous shared
 mappings

I read a post that you made about not being able to expand anonymous 
shared mapping with mremap(). And I am actually having that issue now.

You made the post in 2004 and we are now in 2007. I would like to know 
if that feature was added because the code below always fail with bus 
error on my machine. I use glibc 2.5

Thank you for helping.

#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;
}
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/