> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, March 24, 2026 8:03 AM
> 
> On Wed, Mar 18, 2026 at 08:10:01PM -0700, Nicolin Chen wrote:
> > On Thu, Mar 19, 2026 at 02:29:38AM +0000, Tian, Kevin wrote:
> > > > > > This series addresses a critical vulnerability and stability issue where
> an
> > > > > > unresponsive PCIe device failing to process ATC (Address Translation
> > > > Cache)
> > > > > > invalidation requests leads to silent data corruption and continuous
> > > > SMMU
> > > > > > CMDQ error spam.
> > > > > >
> > > > >
> > > > > None of the patches in this series contains a Fixed tag and cc stable.
> > > >
> > > > Hmm, I guess AI overly polished the cover letter so it sounds too
> > > > strong?
> > > >
> > > > This is essentially a vulnerability (potential memory corruption).
> > > > And none of these patches actually fixes any regression. The PATCH
> > > > 7 even requires the arm_smmu_invs series which has not been merged
> > > > yet :-/
> > > >
> > >
> > > Fixes tag and backporting are not just for regression. People certainly
> > > want to see reported vulnerabilities fixed in stable kernels...
> >
> > Well, maybe I'll just leave additional line telling people that this
> > can't be a bug "fix" because it's written on another unmerged series?
> 
> I think this is more of a feature (RAS support for SMMUv3) than a
> specific fix.
> 

Not a RAS guy, but below is what I got from AI:

"
RAS improvements typically involve better error reporting, graceful
degradation, or improved recovery - but they usually don't involve
scenarios where the system continues operating with compromised
security assumptions."

On Wed, Mar 25, 2026 at 06:55:40AM +0000, Tian, Kevin wrote:
> > I think this is more of a feature (RAS support for SMMUv3) than a
> > specific fix.
> > 
> 
> Not a RAS guy, but below is what I got from AI:
> 
> "
> RAS improvements typically involve better error reporting, graceful
> degradation, or improved recovery - but they usually don't involve
> scenarios where the system continues operating with compromised
> security assumptions."

Right, so currently there is no RAS in smmuv3, if it hits this error
it continues with "compromised security assumptions". Adding RAS
support is to avoid this.

Jason