On 13.11.24 17:18, Vlastimil Babka wrote:
On 11/13/24 17:09, David Hildenbrand wrote:
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Hi, we've seen this in our 5.14 based kernel and it involved the out of
tree gpfs module, but I believe the same thing can happen in LTS's 5.10
and 5.15 without out of tree modules as well. So I'd like your opinion
on this fix before I propose it to stable as a non-standard
version-specific fix (I don't think we'd want to backport fb3d824d1a46
with prerequisities). Thanks.
I recall seeing+discussing this exact patch already a couple years ago :D
Ah, here is the 5.15 version
https://lkml.kernel.org/r/20221028075244.3112566-1-songyuanzheng@xxxxxxxxxx
And the 5.10 version
https://lore.kernel.org/lkml/20221024094911.3054769-1-songyuanzheng@xxxxxxxxxx/
... I could have sworn they got applied.
... and in linux-5.10.y I see
commit 935a8b6202101d7f58fe9cd11287f9cec0d8dd32
Author: Yuanzheng Song <songyuanzheng@xxxxxxxxxx>
Date: Fri Oct 28 03:07:05 2022 +0000
mm/memory: add non-anonymous page check in the copy_present_page()
The vma->anon_vma of the child process may be NULL because
the entire vma does not contain anonymous pages. In this
case, a BUG will occur when the copy_present_page() passes
a copy of a non-anonymous page of that vma to the
page_add_new_anon_rmap() to set up new anonymous rmap.
Maybe you missed that the PageAnon() check is simply a couple of lines
further down in there?
No I was only looking at the 5.15 branch so far, and seems it was never
applied there, unlike 5.10. Weird. But thanks for the heads up.
Indeed, looks like it never got applied to 5.15 ...
--
Cheers,
David / dhildenb
