Re: ia64 port needs help in order to be saved

On 05.08.20 15:30, John Paul Adrian Glaubitz wrote:
> Hello!
>
> On 8/5/20 2:51 PM, John Paul Adrian Glaubitz wrote:
>>> So latest 4.14.x kernels should work w/o the patch on a rx2800 i2 with
>>> Itanium 9300 (Tukwila) series processors - if they are compiled with gcc 10.
>>
>> I'm currently running a 4.14.192 kernel with the ptrace patch. While it doesn't
>> crash, I'm seeing a kworker thread with rather high load.
>>
>> Do you observe that as well?
>
> I have tried 4.19.137 now with the same configuration and Sergey's ptrace patch
> and sure enough it crashes when loading the first modules.

I think this is due to:

```
rx2800-i2 /usr/src/linux-on-ramdisk # git bisect good
543cea9accd9804307541cb93d3ed7ec94b07237 is the first bad commit
commit 543cea9accd9804307541cb93d3ed7ec94b07237
Author: Christoph Hellwig <[email protected]>
Date:   Sun Dec 24 15:10:07 2017 +0100

     ia64: use generic swiotlb_ops

     These are identical to the ia64 ops, and would also support CMA
     if enabled on ia64.

     Signed-off-by: Christoph Hellwig <[email protected]>
     Acked-by: Christian König <[email protected]>

:040000 040000 5fe9ea16dd24746410a88e8e57d5722eabf99650
3cdc996c27f5b5f1cb626dcfe246146e09cb804c M      arch
```

The bisecting happened between 4.15.18 ([1]) - which still ran on my
rx2800 i2 - and 4.16-rc1 ([2]) - which crashes it during OS bootup.

[1]:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v4.15.18&id=a8ec862fda39d9adb88469eb8b9125daccc1c8335

[2]:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v4.16-rc1&id=7928b2cbe55b2a410a0f5c1f154610059c57b1b2

Maybe you try to apply Chrisoph Hellwig's patch from [3] (whole thread
on [4])? If it works then, it could to be related.

[3]: https://marc.info/?l=linux-ia64&m=156145878523498&w=2

[4]: https://marc.info/?l=linux-ia64&m=156144480821712&w=2

Cheers,
Frank