Messages in this thread | | | Date | Wed, 13 May 2015 11:08:23 +0300 | From | Vladimir Davydov <> | Subject | Re: [PATCH v2] rmap: fix theoretical race between do_wp_page and shrink_active_list |
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On Tue, May 12, 2015 at 03:28:40PM -0700, Andrew Morton wrote: > Please let's not put things like WRITE_ONCE() in there without > documenting them - otherwise it's terribly hard for readers to work out > why it was added. > > How's this look? > > --- a/mm/rmap.c~rmap-fix-theoretical-race-between-do_wp_page-and-shrink_active_list-fix > +++ a/mm/rmap.c > @@ -950,6 +950,11 @@ void page_move_anon_rmap(struct page *pa > VM_BUG_ON_PAGE(page->index != linear_page_index(vma, address), page); > > anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; > + /* > + * Ensure that anon_vma and the PAGE_MAPPING_ANON bit are written > + * simultaneously, so a concurrent reader (eg shrink_active_list) will > + * not see one without the other. > + */ > WRITE_ONCE(page->mapping, (struct address_space *) anon_vma); > }
Looks good to me.
Thanks, Vladimir
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