Hi Sebastian,

Thank you for the feedback, it is very helpful.
Could you please provide us with a pointer to the bug?

Thanks again!

Regards,
Sergei
On Fri, 2021-01-08 at 09:29 +0100, Sebastian Andrzej Siewior wrote:

On 2021-01-07 17:49:02 [+0100], To Sergei Poselenov wrote:

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On 2020-12-30 14:09:17 [+0300], Sergei Poselenov wrote:

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Hello,

Hi,

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We applied patch-5.4.47-rt28.patch to NXP 5.4.47-2.2.0 release
ARM64
kernel running on IMX8M NANO chip, and enabled CONFIG_PRREMPT_RT.
We
are observing the following crash (below), on a system running an
application that communicates with some SPI device. Obviously,
the
system doesn't crash without the patch applied.

Any thoughts on the reason of the failure would be appreciated.
How would we start debugging the problem?

Can you give v5.10 a try v5.10 and/or enable SLUB_DEBUG?

Now that I look at it again, you need update to more recent v5.4-RT
kernel. The current is v5.4.84-rt47, the bug was fixed in v5.4.54-
rt33.

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Thanks!

Regards,
Sergei Poselenov,
Emcraft Systems

Sebastian