RE: [APS-24624] Missing patch in K5.15 against kernel panic

["Bilge Aydin" <b.aydin@samsung.com>]

Hello Greg,

Thank you very much for your prompt reply.

"So why do you feel it is required in 5.15.y?"
--> We have faced the issue in our K5.15 based platform. Our technical team has made an investigation and found your given patch. Afterwards we verified it by running a stress test. The result was positive and we did not face the kernel panic again.

Since we are not OS experts, we fully respect Linux community's decisions. That's why we do not see ourselves in that high position to give any guidance and share any patch with you. During our investigation, we only recognized that the given patch was already integrated into the Android common kernel. Outgoing from that, I just want to share the indication with you.

Would it be possible for you to start an internal communication within the Linux community for the synchronization of the K5.15 and K6.1 mainlines explicitly for iommu driver?


Best regards
Bilge




-----Original Message-----
From: Greg KH <gregkh@linuxfoundation.org> 
Sent: Tuesday, December 10, 2024 2:33 PM
To: Bilge Aydin <b.aydin@samsung.com>
Cc: stable@vger.kernel.org
Subject: Re: [APS-24624] Missing patch in K5.15 against kernel panic

On Tue, Dec 10, 2024 at 02:23:35PM +0100, Bilge Aydin wrote:
> Dear Linux community,
> 
> I am leading a project at Samsung where we utilized your kernel 5.15 in our system. Recently we faced an important kernel panic issue whose fix must be following patch:
> https://lore.kernel.org/all/1946ef9f774851732eed78760a78ec40dbc6d178.1
> 667591503.git.robin.murphy@arm.com/
> 
> The problem for us is that this patch must be available from kernel 6.1 onwards. 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/
> drivers/iommu/iommu.c?h=v6.1.119 Clear to us is that it is not 
> integrated into K5.15 yet: 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/
> drivers/iommu/iommu.c?h=v5.15.173
> 
> On the other side we can see that this patch was already applied to 
> Android Common Kernel android13-5.15  
> https://android-review.googlesource.com/q/I51dbcdc5dc536b0e69c6187b2d7
> ac6a2031a305b. In particular, we can see the same implementation in 
> the recent ACK release 
> https://android.googlesource.com/kernel/common/+/refs/tags/android13-5
> .15-2024-11_r2/drivers/iommu/iommu.c  given on 
> https://source.android.com/docs/core/architecture/kernel/gki-android13
> -5_15-release-builds
> 
> Do you have any plan to adjust your implementation in drivers/iommu/iommu.c in K5.15 as present in K6.1? If not, since the issue in our project is very critical for us, may I ask you kindly to trigger the sync of K5.15 and K6.1 soon?

If you wish for a commit to be backported to the stable kernels, just ask us, and better yet, provide a working patch to do so.

The reason we did NOT backport this specific commit is that it is marked as a fix for a commit that shows up in the 6.1 release, so why would it be applicable to 5.15.y at all?  So why do you feel it is required in 5.15.y?  (Note, we have no idea why it's in an Android kernel tree, perhaps they have the offending commit in there as well so the backport is required?  Have you checked?)

If you need or want it applied to older kernels, please send us a working patch and we will be glad to take it.

thanks,

greg k-h