Re: [BUG] ext4 trace events cause NULL pointer dereferences

From: KOSAKI Motohiro
Date: Fri Jul 23 2010 - 01:47:45 EST


> On Thu, Jul 22, 2010 at 01:49:57AM -0400, Christoph Hellwig wrote:
> >
> > I think ext4 is simply using an incorrectly typed tracepoint here.
> > If you want it to be useful in any way it needs a sb paramter and
> > an optional inode paramter, not the allocation context.
>
> I agree; this is the patch that I had whipped up to fix the problem.
> (See below)

I'm not familiar ext4 so much. but you patch seems very nice!
thank you :)

>
> > Also the whole ext4_mb_release_group_pa function seems to be a bit
> > misdesigned. The code using ac is a totally separate block at the
> > end of the function and does work that's unrelated to the rest
> > of the function. Just making it a separate helper can calling it
> > only from those places that have the allocation context would make
> > the code more clear.
>
> I need to look more closely at this. If I had time there would be a
> lot of things that I'd be refactoring and cleaning up in mballoc.c....


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