Subject: Re: [linux-next/mainline][bisected 3acac06][ppc] Oops when unloading mpt3sas driver

From: Abdul Haleem <[email-masked]>
Date: Fri, 20 Mar 2020 15:29:42 +0530

On Tue, 2020-02-25 at 12:23 +0530, Sreekanth Reddy wrote:
> On Tue, Feb 25, 2020 at 11:51 AM Abdul Haleem
> <[email-masked]> wrote:
> >
> > On Fri, 2020-01-17 at 18:21 +0530, Abdul Haleem wrote:
> > > On Thu, 2020-01-16 at 09:44 -0800, Christoph Hellwig wrote:
> > > > Hi Abdul,
> > > >
> > > > I think the problem is that mpt3sas has some convoluted logic to do
> > > > some DMA allocations with a 32-bit coherent mask, and then switches
> > > > to a 63 or 64 bit mask, which is not supported by the DMA API.
> > > >
> > > > Can you try the patch below?
> > >
> > > Thank you Christoph, with the given patch applied the bug is not seen.
> > >
> > > rmmod of mpt3sas driver is successful, no kernel Oops
> > >
> > > Reported-and-tested-by: Abdul Haleem <[email-masked]>
> >
> > Hi Christoph,
> >
> > I see the patch is under discussion, will this be merged upstream any
> > time soon ? as boot is broken on our machines with out your patch.
> >
> 
> Hi Abdul,
> 
> We have posted a new set of patches to fix this issue. This patch set
> won't change the DMA Mask on the fly and also won't hardcode the DMA
> mask to 32 bit.
> 
> [PATCH 0/5] mpt3sas: Fix changing coherent mask after allocation.
> 
> This patchset will have below patches, Please review and try with this
> patch set.
> 
> Suganath Prabu S (5):
>   mpt3sas: Don't change the dma coherent mask after      allocations
>   mpt3sas: Rename function name is_MSB_are_same
>   mpt3sas: Code Refactoring.
>   mpt3sas: Handle RDPQ DMA allocation in same 4g region
>   mpt3sas: Update version to 33.101.00.00

Hi Suganath, 

The above patch fixes the issue, driver is loading and unloading with no
kernel oops. 

Reported-and-tested-by: Abdul Haleem <[email-masked]>

-- 
Regard's

Abdul Haleem
IBM Linux Technology Centre