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

[Ted Ts'o]

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)

> 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....

       	      	       	  	      	  	   - Ted