On Thu, Dec 07, 2017 at 11:22:50AM +0100, Jack Wang wrote: > From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > > commit 0a85e51d37645e9ce57e5e1a30859e07810ed07c upstream. > > Patch series "thp: fix few MADV_DONTNEED races" > > For MADV_DONTNEED to work properly with huge pages, it's critical to not > clear pmd intermittently unless you hold down_write(mmap_sem). > > Otherwise MADV_DONTNEED can miss the THP which can lead to userspace > breakage. > > See example of such race in commit message of patch 2/4. > > All these races are found by code inspection. I haven't seen them > triggered. I don't think it's worth to apply them to stable@. > > This patch (of 4): What about all 4 of these? And should this also go into 4.9? I don't want to include fixes into 4.4-stable without them also being in 4.9-stable, as that would be a regression for people upgrading. thanks, greg k-h