On 06/03/2016 10:33 PM, Guilherme G. Piccoli wrote:
> On 06/03/2016 06:36 PM, Sasha Levin wrote:
>> From: "Guilherme G. Piccoli" <gpiccoli@xxxxxxxxxxxxxxxxxx>
>>
>> This patch has been added to the 4.1 stable tree. If you have any
>> objections, please let us know.
>>
>> ===============
>>
>> [ Upstream commit 8445a87f7092bc8336ea1305be9306f26b846d93 ]
>>
>> Commit 39baadbf36ce ("powerpc/eeh: Remove eeh information from pci_dn")
>> changed the pci_dn struct by removing its EEH-related members.
>> As part of this clean-up, DDW mechanism was modified to read the device
>> configuration address from eeh_dev struct.
>>
>> As a consequence, now if we disable EEH mechanism on kernel command-line
>> for example, the DDW mechanism will fail, generating a kernel oops by
>> dereferencing a NULL pointer (which turns to be the eeh_dev pointer).
>>
>> This patch just changes the configuration address calculation on DDW
>> functions to a manual calculation based on pci_dn members instead of
>> using eeh_dev-based address.
>>
>> No functional changes were made. This was tested on pSeries, both
>> in PHyp and qemu guest.
>>
>> Fixes: 39baadbf36ce ("powerpc/eeh: Remove eeh information from pci_dn")
>> Cc: stable@xxxxxxxxxxxxxxx # v3.4+
>> Reviewed-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
>
>
> Hi Sasha, thanks for letting me know.
>
> Unfortunately, this patch has an issue; the proposed fix is simple and was already sent to linuxppc-dev list by Gavin Shan.
>
> Link to the proposed fix (already tested): https://patchwork.ozlabs.org/patch/626492
>
> Thanks, and sorry for the inconvenience.
> Cheers,
>
>
> Guilherme
Hey Guilherme,
Since the fix isn't in Linus's tree yet, I'll revert this commit from both 4.1 and 3.18
and re-add it into the next release.
Thanks for the report.
Thanks,
Sasha
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