On Thu, Oct 8, 2020 at 2:27 AM Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> wrote: > > In copy_present_page, after we mark the pte non-writable, we should > check for previous dirty bit updates and make sure we don't lose the dirty > bit on reset. No, we'll just remove that entirely. Do you have a test-case that shows a problem? I have a patch that I was going to delay until 5.10 because I didn't think it mattered in practice.. The second part of this patch would be to add a sequence count protection to fast-GUP pinning, so that GUP and fork() couldn't race, but I haven't written that part. Here's the first patch anyway. If you actually have a test-case where this matters, I guess I need to apply it now.. Linus
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