On 11/13/24 17:09, David Hildenbrand wrote: >> --- >> 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.
