Re: [PATCH] Fix mmap_kmem (was: [question] What's the difference between /dev/kmem and /dev/mem)

Andi Kleen
2005-08-12T16:54:54Z

Linus Torvalds <torvalds@osdl.org> writes:
>
> I'm actually more inclined to try to deprecate /dev/kmem.. I don't think
> anybody has ever really used it except for some rootkits.

I don't think that's true.

> So I'd be perfectly happy to fix this, but I'd be even happier if we made
> the whole kmem thing a config variable (maybe even default it to "off").

Acessing vmalloc in /dev/mem would be pretty awkward. Yes it doesn't
also work in mmap of /dev/kmem, but at least in read/write.
There are quite a lot of scripts that use it for kernel debugging
like dumping variables. And for that you really want to access modules
and vmalloc. And it's much easier to parse than /proc/kcore

In fact I have some patches queued to fix it for x86-64 again
(people who used such scripts on i386 are complaining)

-Andi