Re: Patch "khugepaged: khugepaged_test_exit() check mmget_still_valid()" has been added to the 5.8-stable tree

Sasha Levin
2020-08-24T15:31:18Z

On Sat, Aug 22, 2020 at 07:16:39PM -0700, Hugh Dickins wrote:
>On Sat, 22 Aug 2020, Sasha Levin wrote:
>>
>> I've followed your instructions and backported the patches:
>>
>> bbe98f9cadff ("khugepaged: khugepaged_test_exit() check
>> mmget_still_valid()") - to all branches.
>> f3f99d63a815 ("khugepaged: adjust VM_BUG_ON_MM() in
>> __khugepaged_enter()") - to all branches.
>> 59ea6d06cfa9 ("coredump: fix race condition between collapse_huge_page()
>> and core dumping") - for 4.4.
>
>That's saved me time, thanks a lot for doing that work, Sasha.
>
>I've checked the results (haha, read on) and they're all fine,
>but one minor flaw in bisectability: the added 4.4 backport of
>"coredump: fix race condition..." adds a line (deleted by the next commit)
> result = SCAN_ANY_PROCESS;
>but neither "result" nor "SCAN_ANY_PROCESS" is defined in that tree,
>so that intermediate step would generate an easily fixed build error.
>
>FWIW - I don't know whether that's something to care about or not.

I'd probably prefer leaving it this way rather than dragging in more
patches or modifying the existing ones given that it doesn't effect
anything beyond bisectability.

--
Thanks,
Sasha