From: Shigeru Yoshida Date: Sun, 21 Aug 2022 18:35:47 +0000 (+0900) Subject: mm/gup.c: Fix return value for __gup_longterm_locked() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=11147539df44e6165b59d4b0e9a13b91823428e2;p=users%2Fjedix%2Flinux-maple.git mm/gup.c: Fix return value for __gup_longterm_locked() __get_user_pages_locked() may return the number of pages less than nr_pages. So __gup_longterm_locked() have to return the number of pages __get_user_pages_locked() returns if it succeeded, not nr_pages requested. Link: https://lkml.kernel.org/r/20220821183547.950370-1-syoshida@redhat.com Fixes: 61c63c2076d9 (mm/gup.c: simplify and fix check_and_migrate_movable_pages() return codes) Signed-off-by: Shigeru Yoshida Reviewed-by: John Hubbard Reported-by: syzbot+616ff0452fec30f4dcfd@syzkaller.appspotmail.com Reviewed-by: Alistair Popple Cc: David Hildenbrand Cc: Hugh Dickins Cc: Jason Gunthorpe Signed-off-by: Andrew Morton --- diff --git a/mm/gup.c b/mm/gup.c index 5aa7531a703b..542cf74c59b0 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2068,22 +2068,22 @@ static long __gup_longterm_locked(struct mm_struct *mm, unsigned int gup_flags) { unsigned int flags; - long rc; + long rc, nr_pinned_pages; if (!(gup_flags & FOLL_LONGTERM)) return __get_user_pages_locked(mm, start, nr_pages, pages, vmas, NULL, gup_flags); flags = memalloc_pin_save(); do { - rc = __get_user_pages_locked(mm, start, nr_pages, pages, vmas, - NULL, gup_flags); - if (rc <= 0) + nr_pinned_pages = __get_user_pages_locked(mm, start, nr_pages, pages, vmas, + NULL, gup_flags); + if (nr_pinned_pages <= 0) break; - rc = check_and_migrate_movable_pages(rc, pages, gup_flags); + rc = check_and_migrate_movable_pages(nr_pinned_pages, pages, gup_flags); } while (rc == -EAGAIN); memalloc_pin_restore(flags); - return rc ? rc : nr_pages; + return rc ? rc : nr_pinned_pages; } static bool is_valid_gup_flags(unsigned int gup_flags)