Re: Bug#322309: Debian woody dpkg no longer works with recent linux kernel.

[Junichi Uekawa]

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.
> > > 
> > Indeed.  This was the sole change in the 1.13.8 release.
> 
> 1.13.8 is more recent than sarge; and I'm not quite sure 
> why sarge successfully installs, and woody fails.

Okay, I've verified that dpkg on sarge doesn't call mmap.
strace snippet:

umask(022)                              = 022
open("/var/lib/dpkg/status", O_RDONLY)  = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
close(3)                                = 0
open("/var/lib/dpkg/updates/", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 3
fstat(3, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
fcntl(3, F_SETFD, FD_CLOEXEC)           = 0
getdents64(3, /* 2 entries */, 4096)    = 48
getdents64(3, /* 0 entries */, 4096)    = 0
close(3)                                = 0
open("/var/lib/dpkg/available", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
close(3)                                = 0
exit_group(0, 0, 0x2aaaaadfc530, 0x2, 0x2aaaaae00640 <unfinished ... exit status


So, the impact is restricted on trying to run woody dpkg 
on newer kernels.


regards,
	junichi
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