On Mon, Apr 03, 2017 at 04:48:15PM +0100, Catalin Marinas wrote: > On Mon, Apr 03, 2017 at 12:37:51PM +0100, Will Deacon wrote: > > On Mon, Apr 03, 2017 at 11:56:29AM +0100, Mark Rutland wrote: > > > On Fri, Mar 31, 2017 at 06:58:45PM +0100, Mark Rutland wrote: > > > > I'm seeing intermittent bad page state splats on arm64 with 4.11-rc3 and > > > > v4.11-rc4. > > > I wasn't able to trigger the issue over the weekend on a kernel with > > > HUGETLBFS disabled. There are known issues with our handling of > > > contiguous entries, and this might be an artefact of that. > > > > After chatting with Punit, it looks like this might be because the GUP > > code doesn't handle huge ptes (which we create using the contiguous hint), > > so follow_page_pte ends up with one of those and goes wrong. In particular, > > the migration code will certainly do the wrong thing. > > > > I'll probably revert the contiguous support (again) if testing indicates > > that it makes this issue disappear. > > It might be worth checking with Punit's patches as well: > > https://marc.info/?l=linux-arm-kernel&m=149089199018167&w=2 I'd given those patches a spin prior to testing v4.11-rc4 with HUGETLBFS disabled. I saw the issue even with those patches applied. Thanks, Mark. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
