Date: Tue, 21 Sep 2004 16:18:47 +0200 (MEST)
From: "Peter Seiderer" <ps.report@gmx.net>
To: linux-kernel@vger.kernel.org
MIME-Version: 1.0
References: <Pine.LNX.4.53.0409210944320.3495@chaos.analogic.com>
Subject: Re: [BUG][2.6.8.1] Nevver dump core while /dev/men is mmaped
Message-ID: <18354.1095776327@www24.gmx.net>
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Sender: linux-kernel-owner@vger.kernel.org
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> On Tue, 21 Sep 2004, Peter Seiderer wrote:
> 
> > Hello,
> > the following short program stops my computer immediately (no more
> > input, telnet etc. possible):
> >
> > --- begin ---
> > #include <stdio.h>
> > #include <sys/types.h>
> > #include <sys/stat.h>
> > #include <fcntl.h>
> > #include <sys/mman.h>
> > #include <assert.h>
> >
> > int main(int argc, char *argv[]) {
> > 	int fd;
> > 	assert((fd = open("/dev/mem", O_RDWR)) != (-1));
> >
> > 	size_t s = 67108864;
> > 	void *m;
> > 	assert((m = mmap(NULL, s, PROT_READ|PROT_WRITE, MAP_SHARED, fd,
> > 0xd0000000)) != NULL);
>          ^^^^^^^^^^^^^^^
>  Incorrect. mmap() returns MAP_FAILED, (void *)-1, when it fails, not
> NULL, (void *)0.
> 
> 
> Cheers,
> Dick Johnson
> Penguin : Linux version 2.4.26 on an i686 machine (5570.56 BogoMips).
>             Note 96.31% of all statistics are fiction.
> 

Shit, you are right! But did not change anything on the bad kernel
behaviour.....the mmap succeeds, and the kernel hangs in elf_core_dump.
Peter

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