Messages in this thread | | | Subject | Re: [PATCH 3/5] mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page() | From | David Hildenbrand <> | Date | Tue, 23 Mar 2021 11:26:43 +0100 |
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On 20.03.21 10:36, Miaohe Lin wrote: > If the zone device page does not belong to un-addressable device memory, > the variable entry will be uninitialized and lead to indeterminate pte > entry ultimately. Fix this unexpectant case and warn about it.
s/unexpectant/unexpected/
> > Fixes: df6ad69838fc ("mm/device-public-memory: device memory cache coherent with CPU") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/migrate.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 20a3bf75270a..271081b014cb 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -2972,6 +2972,13 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, > > swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE); > entry = swp_entry_to_pte(swp_entry); > + } else { > + /* > + * For now we only support migrating to un-addressable > + * device memory. > + */ > + WARN_ON(1); > + goto abort;
Fix it by crashing the kernel with panic_on_warn? :)
If this case can actual happen, than no WARN_ON() - rather a pr_warn_once(). If this case cannot happen, why do we even care (it's not a fix then)?
-- Thanks,
David / dhildenb
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