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([240d:1a:c0d:9f00:4f2f:926a:23dd:8588]) by smtp.gmail.com with ESMTPSA id b2-20020a170902d50200b0016a0bf0ce32sm8628503plg.70.2022.08.22.08.37.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Aug 2022 08:37:31 -0700 (PDT) From: Shigeru Yoshida To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shigeru Yoshida , Alistair Popple , syzbot+616ff0452fec30f4dcfd@syzkaller.appspotmail.com, John Hubbard Subject: [PATCH v2] mm/gup.c: Fix return value for __gup_longterm_locked() Date: Tue, 23 Aug 2022 00:37:13 +0900 Message-Id: <20220822153713.962904-1-syoshida@redhat.com> X-Mailer: git-send-email 2.37.2 MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII"; x-default=true ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661182655; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:in-reply-to: references:dkim-signature; bh=OR0r/hyXZ2PC1LIRo6zlU9kEOJ14T8ubT9gvOTsTo74=; b=Uconsg1CtTCfhFWG+etPgWRDxAXHJi1d2by3vowOLoHTyS49gnP2WD4akh6E9uHz6JZfxv IB/B3RLTl/MHpcp/KxAlMjZ6MFsmhq5zn6ob6Ojvh9gjSnwYiDAwRukavoGHkyHfc9JHWh W1OoNMC8mMGEeCJxseNAFXduEPE3U+U= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="Y/SxaKE7"; spf=pass (imf09.hostedemail.com: domain of syoshida@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=syoshida@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661182655; a=rsa-sha256; cv=none; b=Q0WQljs9VKRn+Q+y0abuOfNf0TnviQ32W52R91we6Fk6NRLs59VbDWpZ0qKCw3UszPNlbh iJr7hX25MLhV3m31N3mVV6SZ6hfXfqdL25A1naPJ2LmB+Dz3a+MzJCJL/QDFB0Lml3fQMh 45MtPucFBFNuPSHFSJ2IZP0TSxMHRao= X-Rspam-User: Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="Y/SxaKE7"; spf=pass (imf09.hostedemail.com: domain of syoshida@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=syoshida@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Stat-Signature: gnsy9ihb6rjgwejie5ahi3opxyu688wg X-Rspamd-Queue-Id: 48496140068 X-Rspamd-Server: rspam08 X-HE-Tag: 1661182654-63626 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: __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. Fixes: 61c63c2076d9 (mm/gup.c: simplify and fix check_and_migrate_movable_pages() return codes) CC: Alistair Popple Reported-by: syzbot+616ff0452fec30f4dcfd@syzkaller.appspotmail.com Reviewed-by: John Hubbard Signed-off-by: Shigeru Yoshida --- mm/gup.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 5aa7531a703b..66582203220a 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2068,22 +2068,24 @@ 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) -- 2.37.2