Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> Hi Greg,
> 
> On Thu, Oct 10, 2024 at 11:07 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > > Hello all,
> > >
> > > We are experiencing a boot hang issue when booting kernel version
> > > 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > > 6710E processor. After extensive testing and use of `git bisect`, we
> > > have traced the issue to commit:
> > >
> > > `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> > >
> > > This commit appears to be part of a larger patchset, which can be found here:
> > > [Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> > >
> > > We attempted to boot with the `intel_iommu=off` option, but the system
> > > hangs in the same manner. However, the system boots successfully after
> > > disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> >
> > Is there any error messages?  Does the latest 6.6.y tree work properly?
> > If so, why not just use that, no new hardware should be using older
> > kernel trees anyway :)
> No error, just hang, I've removed "quiet" and added "debug".
> Yes, the latest 6.6.y tree works for this, but there are other
> problems/dependency we have to solve.

Ok, that implies that we need to add some other patch to 6.1.y, OR we
can revert it from 6.1.y.  Let me know what you think is the better
thing to do.

thanks,

greg k-h