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

[Baolu Lu <baolu.lu@linux.intel.com>]

On 2024/10/10 21:25, Liang, Kan wrote:
> On 2024-10-10 6:10 a.m., Jinpu Wang wrote:
>> Hi Greg,
>>
>>
>> On Thu, Oct 10, 2024 at 11:31 AM Greg KH<gregkh@linuxfoundation.org> wrote:
>>> 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.
>>>
>> I think better to revert both:
>> 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
> I'm not sure about this one. May need baolu's comments.

I can't find this commit in the mainline kernel. I guess it fixes a
compilation issue in the stable tree? If so, it depends on whether the
issue is still there.

Thanks,
baolu