Messages in this thread | | | From | Pankaj Gupta <> | Date | Thu, 30 Jul 2020 06:21:33 +0200 | Subject | Re: [PATCH v1 2/6] mm/page_isolation: don't dump_page(NULL) in set_migratetype_isolate() |
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> Right now, if we have two isolations racing, we might trigger the > WARN_ON_ONCE() and to dump_page(NULL), dereferencing NULL. Let's just > return directly. > > In the future, we might want to report -EAGAIN to the caller instead, as > this could indicate a temporary isolation failure only. > > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Michael S. Tsirkin <mst@redhat.com> > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > mm/page_isolation.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/mm/page_isolation.c b/mm/page_isolation.c > index f6d07c5f0d34d..553b49a34cf71 100644 > --- a/mm/page_isolation.c > +++ b/mm/page_isolation.c > @@ -29,10 +29,12 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_ > /* > * We assume the caller intended to SET migrate type to isolate. > * If it is already set, then someone else must have raced and > - * set it before us. Return -EBUSY > + * set it before us. > */ > - if (is_migrate_isolate_page(page)) > - goto out; > + if (is_migrate_isolate_page(page)) { > + spin_unlock_irqrestore(&zone->lock, flags); > + return -EBUSY; > + } > > /* > * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. > --
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
> 2.26.2 > >
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