Re: [BUG 2.6.17-git] kmem_cache_create: duplicate cache scsi_cmd_cache

Linus Torvalds
2006-05-12T17:37:15Z

On Fri, 12 May 2006, Erik Mouw wrote:

> On Fri, May 12, 2006 at 06:53:27AM +0200, Or Gerlitz wrote:
> >
> > I was pointing on 2.6.17 kmem_cache related issues while back to LKML
> > and it turns out that you can reproduce them easily with standalone
> > trivial module, see
> > http://openib.org/pipermail/openib-general/2006-April/020582.html
> >
> > So far no one picked the issue anb i was adviced to use bisection...
>
> I tracked it down with git bisect. The culprit is this commit:
>
> 56cf6504fc1c0c221b82cebc16a444b684140fb7 is first bad commit

Ok, that's just _strange_. Clearly bisection picked the right commit,
since:

> After reverting this commit in 2.6.17-rc4 I can't trigger the bug
> anymore.

but at the same time, I don't see what that two-liner patch to
block/genhd.c has to do with that trivial module which doesn't even _use_
any of the functions that the patch affects.

It sounds like you used some other test-case than the trivial module above
to test bisection?

So when you say "I tracked _it_ down with git bisect" (my emphasis), it
sounds like "it" was really something else than the trivial stand-alone
module. Or are you saying that the trivial stand-alone module _also_ got
fixed?

> Might be worth fixing before 2.6.17-final.

Yes. We could just revert that commit, but it seems correct, and I'd
really like for somebody to understand _why_ that commit matters at all. I
certainly don't see the overlap here..

So I get the feeling that you bisected just the case below, right?

> Note: I'm going on holiday next week, so I'm not able to test any
> fixes. However, because this bug is very easy to trigger[1], anybody
> with root on NFS and fully modular SCSI or libata should be able to
> test.
>
> [1] See http://marc.theaimsgroup.com/?l=linux-scsi&m=114736053211943&w=2

Hmm. Jens? Any ideas?

Linus