On Thu, 24 May 2018 09:44:16 +0100 Suzuki K Poulose <Suzuki.Poulose@xxxxxxx> wrote: > On 14/05/18 10:45, Suzuki K Poulose wrote: > > On 10/05/18 00:31, Andrew Morton wrote: > >> On Fri, 4 May 2018 11:11:46 +0800 Jia He <hejianet@xxxxxxxxx> wrote: > >> > >>> In our armv8a server(QDF2400), I noticed lots of WARN_ON caused by PAGE_SIZE > >>> unaligned for rmap_item->address under memory pressure tests(start 20 guests > >>> and run memhog in the host). > >>> > >>> ... > >>> > >>> In rmap_walk_ksm, the rmap_item->address might still have the STABLE_FLAG, > >>> then the start and end in handle_hva_to_gpa might not be PAGE_SIZE aligned. > >>> Thus it will cause exceptions in handle_hva_to_gpa on arm64. > >>> > >>> This patch fixes it by ignoring(not removing) the low bits of address when > >>> doing rmap_walk_ksm. > >>> > >>> Signed-off-by: jia.he@xxxxxxxxxxxxxxxx > >> > >> I assumed you wanted this patch to be committed as > >> From:jia.he@xxxxxxxxxxxxxxxx rather than From:hejianet@xxxxxxxxx, so I > >> made that change. Please let me know if this was inappropriate. > >> > >> You can do this yourself by adding an explicit From: line to the very > >> start of the patch's email text. > >> > >> Also, a storm of WARN_ONs is pretty poor behaviour. Is that the only > >> misbehaviour which this bug causes? Do you think the fix should be > >> backported into earlier kernels? > >> > > > Jia, Andrew, > > What is the status of this patch ? > I have it scheduled for 4.18-rc1, with a cc:stable for backporting. I'd normally put such a fix into 4.17-rcX but I'd like to give Hugh time to review it and to generally give it a bit more time for review and test. Have you tested it yourself?
