From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:36428 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725616AbfFNBUB (ORCPT ); Thu, 13 Jun 2019 21:20:01 -0400 Date: Fri, 14 Jun 2019 09:19:47 +0800 From: Ming Lei Subject: Re: alternative take on the same page merging leak fix v2 Message-ID: <20190614011946.GB14436@ming.t460p> References: <20190613095529.25005-1-hch@lst.de> <00c908ad-ca33-164d-3741-6c67813c1f0d@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00c908ad-ca33-164d-3741-6c67813c1f0d@kernel.dk> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Jens Axboe Cc: Christoph Hellwig , David Gibson , "Darrick J. Wong" , linux-block@vger.kernel.org, linux-xfs@vger.kernel.org On Thu, Jun 13, 2019 at 04:04:03AM -0600, Jens Axboe wrote: > On 6/13/19 3:55 AM, Christoph Hellwig wrote: > > Hi Jens, hi Ming, > > > > this is the tested and split version of what I think is the better > > fix for the get_user_pages page leak, as it leaves the intelligence > > in the callers instead of in bio_try_to_merge_page. > > > > Changes since v1: > > - drop patches not required for 5.2 > > - added Reviewed-by tags > > Applied for 5.2, thanks. Hi Jens & Christoph, Looks the following change is missed in patch 1, otherwise kernel oops is triggered during kernel booting: diff --git a/block/bio.c b/block/bio.c index 35b3c568a48f..9ccf07c666f7 100644 --- a/block/bio.c +++ b/block/bio.c @@ -706,6 +706,8 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio, return 0; if (bio->bi_vcnt > 0) { + bool same_page; + bvec = &bio->bi_io_vec[bio->bi_vcnt - 1]; if (page == bvec->bv_page && @@ -723,7 +725,7 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio, if (bvec_gap_to_prev(q, bvec, offset)) return 0; - if (page_is_mergeable(bvec, page, len, offset, false) && + if (page_is_mergeable(bvec, page, len, offset, &same_page) && can_add_page_to_seg(q, bvec, page, len, offset)) { bvec->bv_len += len; goto done; Thanks, Ming