From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64FE5C56202 for ; Mon, 23 Nov 2020 12:55:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 105DE20657 for ; Mon, 23 Nov 2020 12:55:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="18Cr4Qav" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387899AbgKWMy5 (ORCPT ); Mon, 23 Nov 2020 07:54:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:36852 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387863AbgKWMxG (ORCPT ); Mon, 23 Nov 2020 07:53:06 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0CB8121D7A; Mon, 23 Nov 2020 12:52:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1606135959; bh=8+/o72ugXJRo3qLpZVgZ+PPX9JIuk3UxkdFOcvmMnPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=18Cr4QavnbrKus5u5Qvg9WN7SixFdJR3/E+yD6qAhZ7tOfG8uGIwbLEDT7RY20Gof 1pK9g11XVPLyUpEA62JKBBbCSd+ocwZTMxzXBW9A9mtqnkUM/qVZA/oDZdIfbEkg4D Dn4WtDnF0eXcoqKZqUckTDh3teyEohsgIEwr0jLU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jens Axboe Subject: [PATCH 5.9 249/252] mm: never attempt async page lock if weve transferred data already Date: Mon, 23 Nov 2020 13:23:19 +0100 Message-Id: <20201123121847.604526424@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123121835.580259631@linuxfoundation.org> References: <20201123121835.580259631@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jens Axboe commit 0abed7c69b956d135cb6d320c350b2adb213e7d8 upstream. We catch the case where we enter generic_file_buffered_read() with data already transferred, but we also need to be careful not to allow an async page lock if we're looping transferring data. If not, we could be returning -EIOCBQUEUED instead of the transferred amount, and it could result in double waitqueue additions as well. Cc: stable@vger.kernel.org # v5.9 Fixes: 1a0a7853b901 ("mm: support async buffered reads in generic_file_buffered_read()") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- mm/filemap.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2327,10 +2327,15 @@ page_ok: page_not_up_to_date: /* Get exclusive access to the page ... */ - if (iocb->ki_flags & IOCB_WAITQ) + if (iocb->ki_flags & IOCB_WAITQ) { + if (written) { + put_page(page); + goto out; + } error = lock_page_async(page, iocb->ki_waitq); - else + } else { error = lock_page_killable(page); + } if (unlikely(error)) goto readpage_error; @@ -2373,10 +2378,15 @@ readpage: } if (!PageUptodate(page)) { - if (iocb->ki_flags & IOCB_WAITQ) + if (iocb->ki_flags & IOCB_WAITQ) { + if (written) { + put_page(page); + goto out; + } error = lock_page_async(page, iocb->ki_waitq); - else + } else { error = lock_page_killable(page); + } if (unlikely(error)) goto readpage_error;