Re: [Fwd: ps broken]
Albert Cahalan wrote:
> On Mon, 2003-11-10 at 19:21, Prasanna Meda wrote:
>
> > In reply to
> > http://lists.debian.org/debian-user/2002/debian-user-200206/msg01866.html
> >
> > I also noticed the same problem. It is due to
> > ps trying to access the past end of mmaped
> > System.map file in my case. What does your
> > trace show? Is this fixed in later versions?
> > It is mapping one byte more and accessing
> > that byte and is getting SIGBUS.
>
> Back in the Linux 1.x.xx era, Linus deliberately
> made an allowance for the above. It seemed, and
> still seems, to be good kernel behavior. After all,
> an incomplete page is padded with '\0' characters.
> Why should a full page be any different?
>
> Unfortunately, some idiot got SIGBUS into the
> UNIX standard. With regret, Linus changed the
> kernel. This broke even his own mkdep code
> that was part of the kernel build process.
>
> The procps-3.x.xx releases available in recent
> versions of Debian no longer rely on this
> wonderful old Linux feature.
Yes, I see the semantics change in kernel from
2.2 to 2.4, but what is the reason behind your
mapping filesize+1 bytes in first than filesize
bytes?
In my case, the file size is 475136 bytes, that is
exactly 116 pages, mmap is done for 475137
bytes.
Thanks,
Prasanna.
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