Date: Mon, 10 Oct 2005 00:16:38 +0900
Message-ID: <87zmpi3ell.dancerj%dancer@netfort.gr.jp>
From: Junichi Uekawa <dancer@netfort.gr.jp>
To: 322309-submitter@bugs.debian.org, 322309@bugs.debian.org,
       329468@bugs.debian.org, 329468-submitter@bugs.debian.org,
       debian-devel@bugs.debian.org, linux-kernel@vger.kernel.org,
       332903-submitter@bugs.debian.org
Subject: Debian woody dpkg no longer works with recent linux kernel.
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Hi,

dpkg in Debian woody (3.0) is broken by recent linux kernels;
due to the following command changing behavior (mmap of 
zero-byte length):

  addr=mmap(NULL, 0, PROT_READ, MAP_SHARED, fd, 0);

These bugs are caused by mmap changing behavior; 
it used to return NULL when given a length of 0.
However, it now returns -1, and gives back an errno=EINVAL.

This triggers problems in Debian installation.
The workaround is to give some content to the files:
/var/lib/status
/var/lib/available


$ uname -r
2.6.14-rc3dancer-gedb4a353
$ ./a.c b
a.c: In function 'main':
a.c:26: warning: comparison between pointer and integer
mmap: Invalid argument
$ ls -l b
-rw-r--r--  1 dancer dancer 0 2005-10-09 22:29 b


$ uname -r
2.2.26
$ cat a.c
/*BINFMTC:
 * */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>

int main(int argc, char **argv)
{
  int fd;
  void*addr;
  if (argc < 2)
    {
      fprintf(stderr, "Filename required\n");
      return 1;
    }

  if((fd=open(argv[1], O_RDONLY))==-1)
    {
      perror("open");
      return 1;
    }
  addr=mmap(NULL, 0, PROT_READ, MAP_SHARED, fd, 0);
  if (addr==-1)
    {
      perror("mmap");
      return 1;
    }
  printf ("%p\n", addr);
  if(close(fd)==-1)
    {
      perror("close");
      return 1;
    }
  return 0;
}
$ ./a.out b
(nil)


regards,
	junichi
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