On Mon, Jun 11, 2018 at 01:55:17PM +0100, Ben Hutchings wrote: > On Mon, 2018-05-28 at 12:00 +0200, Greg Kroah-Hartman wrote: > > 4.4-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > > > > [ Upstream commit c58f0bb77ed8bf93dfdde762b01cb67eebbdfc29 ] > > > > Patch series "Do not lose dirty bit on THP pages", v4. > > > > Vlastimil noted that pmdp_invalidate() is not atomic and we can lose > > dirty and access bits if CPU sets them after pmdp dereference, but > > before set_pmd_at(). > > > > The bug can lead to data loss, but the race window is tiny and I haven't > > seen any reports that suggested that it happens in reality. So I don't > > think it worth sending it to stable. > [...] > > This patch (of 12): > > > > This is an implementation of pmdp_establish() that is only suitable for > > an architecture that doesn't have hardware dirty/accessed bits. In this > > case we can't race with CPU which sets these bits and non-atomic > > approach is fine. > [...] > > There's no point in applying just this patch, since it adds a new > function that nothing will call. > > I tend to think that since this is fixing a potential data loss, the > whole series should be backported. But the commit message here says it > shouldn't. Hm, I thought there was some reason for this patch, as I thought it came up before. Sasha do you remember? Should I just revert it? thanks, greg k-h
