On 01/29/2018 07:54 PM, 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. > > 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. > > Signed-off-by: Naoya Horiguchi <[email protected]> > Acked-by: Michal Hocko <[email protected]> // for v1 > Cc: <[email protected]> > --- > ChangeLog v1 -> v2: > - add comment about what we need to support hwpoision for pud-sized hugetlb > - use "page size > PMD_SIZE" condition instead of hstate_is_gigantic() > --- > include/linux/mm.h | 1 + > mm/memory-failure.c | 16 ++++++++++++++++ > 2 files changed, 17 insertions(+) > > diff --git v4.15-rc8-mmotm-2018-01-18-16-31/include/linux/mm.h > v4.15-rc8-mmotm-2018-01-18-16-31_patched/include/linux/mm.h > index 63f7ba1..6b3df81 100644 > --- v4.15-rc8-mmotm-2018-01-18-16-31/include/linux/mm.h > +++ v4.15-rc8-mmotm-2018-01-18-16-31_patched/include/linux/mm.h > @@ -2607,6 +2607,7 @@ enum mf_action_page_type { > MF_MSG_POISONED_HUGE, > MF_MSG_HUGE, > MF_MSG_FREE_HUGE, > + MF_MSG_NON_PMD_HUGE, > MF_MSG_UNMAP_FAILED, > MF_MSG_DIRTY_SWAPCACHE, > MF_MSG_CLEAN_SWAPCACHE, > diff --git v4.15-rc8-mmotm-2018-01-18-16-31/mm/memory-failure.c > v4.15-rc8-mmotm-2018-01-18-16-31_patched/mm/memory-failure.c > index d530ac1..264e020 100644 > --- v4.15-rc8-mmotm-2018-01-18-16-31/mm/memory-failure.c > +++ v4.15-rc8-mmotm-2018-01-18-16-31_patched/mm/memory-failure.c > @@ -508,6 +508,7 @@ static const char * const action_page_types[] = { > [MF_MSG_POISONED_HUGE] = "huge page already hardware poisoned", > [MF_MSG_HUGE] = "huge page", > [MF_MSG_FREE_HUGE] = "free huge page", > + [MF_MSG_NON_PMD_HUGE] = "non-pmd-sized huge page", > [MF_MSG_UNMAP_FAILED] = "unmapping failed page", > [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page", > [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page", > @@ -1090,6 +1091,21 @@ static int memory_failure_hugetlb(unsigned long pfn, > int trapno, int flags) > return 0; > } > > + /* > + * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so > + * simply disable it. In order to make it work properly, we need > + * make sure that: > + * - conversion of a pud that maps an error hugetlb into hwpoison > + * entry properly works, and > + * - other mm code walking over page table is aware of pud-aligned > + * hwpoison entries. > + */ > + if (huge_page_size(page_hstate(head)) > PMD_SIZE) { > + action_result(pfn, MF_MSG_NON_PMD_HUGE, MF_IGNORED); > + res = -EBUSY; > + goto out; > + } > + > if (!hwpoison_user_mappings(p, pfn, trapno, flags, &head)) { > action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); > res = -EBUSY; >
Thanks, that does catch all those other huge page sizes. Reviewed-by: Mike Kravetz <[email protected]> It would really be helpful to get some comments from the powerpc folks as this does seem to impact them most. Perhaps arm64 as well? -- Mike Kravetz
