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=0.7 required=3.0 tests=BIGNUM_EMAILS, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 46D2BC3A5A1 for ; Wed, 28 Aug 2019 11:05:46 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C74B0208CB for ; Wed, 28 Aug 2019 11:05:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C74B0208CB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46JNFg4RFJzDr7g for ; Wed, 28 Aug 2019 21:05:43 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=huawei.com (client-ip=45.249.212.188; helo=huawei.com; envelope-from=gaoxiang25@huawei.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from huawei.com (szxga02-in.huawei.com [45.249.212.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46JNCL72GjzDr55 for ; Wed, 28 Aug 2019 21:03:42 +1000 (AEST) Received: from DGGEMM404-HUB.china.huawei.com (unknown [172.30.72.55]) by Forcepoint Email with ESMTP id 64B6B34AEBB75AD41776; Wed, 28 Aug 2019 19:03:36 +0800 (CST) Received: from dggeme762-chm.china.huawei.com (10.3.19.108) by DGGEMM404-HUB.china.huawei.com (10.3.20.212) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 28 Aug 2019 19:03:35 +0800 Received: from architecture4 (10.140.130.215) by dggeme762-chm.china.huawei.com (10.3.19.108) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Wed, 28 Aug 2019 19:03:35 +0800 Date: Wed, 28 Aug 2019 19:02:49 +0800 From: Gao Xiang To: Dan Carpenter Subject: Re: [bug report] staging: erofs: introduce erofs_grab_bio Message-ID: <20190828110249.GA56298@architecture4> References: <20190828105541.GA21320@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20190828105541.GA21320@mwanda> User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [10.140.130.215] X-ClientProxiedBy: dggeme710-chm.china.huawei.com (10.1.199.106) To dggeme762-chm.china.huawei.com (10.3.19.108) X-CFilter-Loop: Reflected X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: miaoxie@huawei.com, xiang@kernel.org, linux-erofs@lists.ozlabs.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" Hi Dan, On Wed, Aug 28, 2019 at 01:55:41PM +0300, Dan Carpenter wrote: > Hello Gao Xiang, > > The patch 8be31270362b: "staging: erofs: introduce erofs_grab_bio" > from Aug 21, 2018, leads to the following static checker warning: > > fs/erofs/zdata.c:1272 z_erofs_vle_submit_all() > error: 'bio' dereferencing possible ERR_PTR() > > fs/erofs/zdata.c > 1259 if (bio && force_submit) { > 1260 submit_bio_retry: > 1261 __submit_bio(bio, REQ_OP_READ, 0); > 1262 bio = NULL; > 1263 } > 1264 > 1265 if (!bio) { > 1266 bio = erofs_grab_bio(sb, first_index + i, > 1267 BIO_MAX_PAGES, bi_private, > 1268 z_erofs_vle_read_endio, true); > > This assumes erofs_grab_bio() can't fail. It returns ERR_PTR(-ENOMEM) > on failure. I think there is no problem at all as well. The last argument of erofs_grab_bio is nofail, and here is "true". 415 static inline struct bio *erofs_grab_bio(struct super_block *sb, 416 erofs_blk_t blkaddr, 417 unsigned int nr_pages, 418 void *bi_private, bio_end_io_t endio, 419 bool nofail) 420 { 421 const gfp_t gfp = GFP_NOIO; 422 struct bio *bio; 423 424 do { 425 if (nr_pages == 1) { 426 bio = bio_alloc(gfp | (nofail ? __GFP_NOFAIL : 0), 1); 427 if (unlikely(!bio)) { 428 DBG_BUGON(nofail); 429 return ERR_PTR(-ENOMEM); 430 } 431 break; 432 } 433 bio = bio_alloc(gfp, nr_pages); 434 nr_pages /= 2; 435 } while (unlikely(!bio)); 436 437 bio->bi_end_io = endio; 438 bio_set_dev(bio, sb->s_bdev); 439 bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK; 440 bio->bi_private = bi_private; 441 return bio; 442 } You can see __GFP_NOFAIL is set, Am I missing something? Thanks, Gao Xiang > > 1269 ++nr_bios; > 1270 } > 1271 > 1272 err = bio_add_page(bio, page, PAGE_SIZE, 0); > 1273 if (err < PAGE_SIZE) > 1274 goto submit_bio_retry; > 1275 > 1276 force_submit = false; > 1277 last_index = first_index + i; > 1278 skippage: > 1279 if (++i < clusterpages) > 1280 goto repeat; > > regards, > dan carpenter