Re: [REGRESSION][v4.14.y][v4.15] x86/intel_rdt/cqm: Improve limbo list processing

[Thomas Gleixner]

Vikas, Fenghua can you please look at that ASAP?

On Sun, 14 Jan 2018, Thomas Gleixner wrote:

> On Fri, 12 Jan 2018, Joseph Salisbury wrote:
> 
> > Hi Vikas,
> > 
> > A kernel bug report was opened against Ubuntu [0]. After a kernel
> > bisect, it was found that reverting the following commit resolved this bug:
> > 
> > commit 24247aeeabe99eab13b798ccccc2dec066dd6f07
> > Author: Vikas Shivappa <vikas.shivappa@xxxxxxxxxxxxxxx>
> > Date:ÂÂ Tue Aug 15 18:00:43 2017 -0700
> > 
> > ÂÂÂ x86/intel_rdt/cqm: Improve limbo list processing
> > 
> > 
> > The regression was introduced as of v4.14-r1 and still exists with
> > current mainline. The trace with v4.15-rc7 is in comment #44[1].
> > 
> > I was hoping to get your feedback, since you are the patch author. Do
> > you think gathering any additional data will help diagnose this issue,
> > or would it be best to submit a revert request?
> 
> That stinks like a use after free. Can you run with KASAN enabled?
> 
> Thanks,
> 
> 	tglx