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?
> > 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?
> > Signed-off-by: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
Acked-by: Michal Hocko <mho...@suse.com>
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.
> > ---
> > include/linux/mm.h | 1 +
> > mm/memory-failure.c | 7 +++++++
> > 2 files changed, 8 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..166864e 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_GIGANTIC,
> > 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..c497588 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_GIGANTIC] = "gigantic page",
> > [MF_MSG_UNMAP_FAILED] = "unmapping failed page",
> > [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page",
> > [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page",
> > @@ -1090,6 +1091,12 @@ static int memory_failure_hugetlb(unsigned long pfn,
> > int trapno, int flags)
> > return 0;
> > }
> >
> > + if (hstate_is_gigantic(page_hstate(head))) {
> > + action_result(pfn, MF_MSG_GIGANTIC, 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;
> > --
> > 2.7.0
> >
> >
> --
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--
Michal Hocko
SUSE Labs
