On Monday, July 22, 2019 4:47:51 PM CEST, Matthias Brugger wrote:

On 22/07/2019 16:31, Vicente Bergas wrote:

quoted

Hi, i have been running linux on rk3399 booted with kexec fine until 5.2
From 5.2 onwards, there are memory corruption issues as reported here:
http://lkml.iu.edu/hypermail/linux/kernel/1906.2/07211.html
kexec has been identified as the principal reason for the issues.

It turns out that kexec has never worked reliably on this platform, ...

Is there a known kernel where kexec was working (v5.2 e.g.)?
If you can find one, you can run git bisect to find the commit 
that breaks things.

Yes, most kernels i have tried before 5.2 worked, more or less.
From time to time there were random freezes at boot time.
Re-booting 2 or 3 times fixed it. This was happenning about 1 out of 10 
times.
I've rarely seen kernel traces on dmesg, but these were not affecting the 
stability of the system.
I've also used 5.2 (a known affected version) during days with no issues.
So, the randomness of the issue reproducibility makes bisecting too 
dificult.

Apart from that you should try to enable earlycon on your kernel you want to
kexec into, so at least you can see if it crashes in the new kernel.

Added earlycon to the cmdline. Now it boots fine, although it is not
working, the d_lookup issues are still there.
Basically, it looks like anything that changes the kernel memory layout
(like a single extra alloc) affects the issue, making it completely random.

If you
still don't see anything you can try to use prugatory printing (if you use
kexec_load and not kexec_file_load). I have a work-in-progress 
patches that I
can share with you if needed. Just let me know.

What is 'prugatory printing' ? I am using kexec_load from kexec-tools. The
option to use kexec_file_load is not used.

Regards,
Matthias

quoted

Regards,
 Vicenç.


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