Hi Michal, Mike, On Mon, Jan 29, 2018 at 10:08:53AM -0800, Mike Kravetz wrote: > On 01/29/2018 01:54 AM, Michal Hocko wrote: > > On Mon 29-01-18 06:30:55, Naoya Horiguchi wrote: > >> My apology, I forgot to CC to the mailing lists. > >> > >> On Mon, Jan 29, 2018 at 03:28:03PM +0900, Naoya Horiguchi wrote: > >>> Recently the following BUG was reported: > >>> > >>> Injecting memory failure for pfn 0x3c0000 at process virtual address 0x7fe300000000 > >>> Memory failure: 0x3c0000: recovery action for huge page: Recovered > >>> BUG: unable to handle kernel paging request at ffff8dfcc0003000 > >>> IP: gup_pgd_range+0x1f0/0xc20 > >>> PGD 17ae72067 P4D 17ae72067 PUD 0 > >>> Oops: 0000 [#1] SMP PTI > >>> ... > >>> CPU: 3 PID: 5467 Comm: hugetlb_1gb Not tainted 4.15.0-rc8-mm1-abc+ #3 > >>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.fc25 04/01/2014 > >>> > >>> You can easily reproduce this by calling madvise(MADV_HWPOISON) twice on > >>> a 1GB hugepage. This happens because get_user_pages_fast() is not aware > >>> of a migration entry on pud that was created in the 1st madvise() event. > > > > Do pgd size pages work properly? PGD size is unsupported now too, and this patch is also disabling that size. > > Adding Anshuman and Aneesh as they added pgd support for power. And, > this patch will disable that as well IIUC. Thanks Mike, I want to have some feedback from PowerPC developers too. > > This patch makes sense for x86. My only concern/question is for other > archs which may have huge page sizes defined which are > MAX_ORDER and > < PUD_SIZE. These would also be classified as gigantic and impacted > by this patch. Do these also have the same issue? Maybe one clearer way is to use more explicit condition like "page size > PMD_SIZE". > > -- > Mike Kravetz > > >>> I think that conversion to pud-aligned migration entry is working, > >>> but other MM code walking over page table isn't prepared for it. > >>> We need some time and effort to make all this work properly, so > >>> this patch avoids the reported bug by just disabling error handling > >>> for 1GB hugepage. > > > > Can we also get some documentation which would describe all requirements > > for HWPoison pages to work properly please? OK, I'll add this. > > > >>> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > > > > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > > > > We probably want a backport to stable as well. Although regular process > > cannot get giga pages easily without admin help it is still not nice to > > oops like this. I'll add CC to stable. Thanks, Naoya Horiguchi -- 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
