Re: [PATCH v9 02/10] mm: Non-pmd-mappable, large folios for folio_add_new_anon_rmap()

Sven Schnelle
2024-01-24T12:29:07Z

Hi Ryan,

Ryan Roberts <ryan.roberts@arm.com> writes:

>>>>>>>>> I'm hitting this bug (console output below) with adding uprobe
>>>>>>>>> on simple program like:
>>>>>>>>>
>>>>>>>>> $ cat up.c
>>>>>>>>> int main(void)
>>>>>>>>> {
>>>>>>>>> return 0;
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> # bpftrace -e 'uprobe:/home/jolsa/up:_start {}'
>>>>>>>>>
>>>>>>>>> $ ./up
>>>>>>>>>
>>>>>>>>> it's on top of current linus tree master:
>>>>>>>>> 052d534373b7 Merge tag 'exfat-for-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat
>>>>>>>>>
>>>>>>>>> before this patch it seems to work, I can send my .config if needed
>>>>>>
>>>>>> Thanks for the bug report!
>>>>>
>>>>> I just hit the same bug in our CI, but can't find the fix in -next. Is
>>>>> this in the queue somewhere?
>>>>
>>>> we hit it as well, but I can see the fix in linux-next/master
>>>>
>>>> 4c137bc28064 uprobes: use pagesize-aligned virtual address when replacing pages
>>>
>>> Yes that's the one. Just to confirm: you are still hitting the VM_BUG_ON despite
>>> having this change in your kernel? Could you please send over the full bug log?
>>
>> ah sorry.. I meant the change fixes the problem for us, it just did not
>> yet propagate through the merge cycle into bpf trees.. but I can see it
>> in linux-next tree, so it's probably just matter of time
>
> OK great! How about you, Sven? Do you have this change in your kernel? Hopefully
> it should fix your problem.

Same here - the fix makes uprobes work again, i just didn't see it in
torvalds-master and neither in todays linux-next. But Jiri is right,
it's in linux-next/master. I just missed to find it there. So everything
should be ok.