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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 1B7C1C2B9F8 for ; Mon, 24 May 2021 15:37:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0270661416 for ; Mon, 24 May 2021 15:37:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234079AbhEXPie (ORCPT ); Mon, 24 May 2021 11:38:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:50498 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232829AbhEXPe4 (ORCPT ); Mon, 24 May 2021 11:34:56 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C3AC4613C8; Mon, 24 May 2021 15:32:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621870340; bh=ZP1z6xfZ4sra0aSKN20GNNlBCH2m0BhCbrHOQLCUcJo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jxMY+jA0ClVYNcwTusj/ogDimx19oPZf/2l8YrtYq+8R5Llm52EJIS8obkybWHyBa u0EqB9hc4w+8nrhZjASMIfzCVp1REa2Xf0HEUn0R5zCCjvw2BY/9R6qlhqlCHMtSTL LCu4W95LObOoqZRFmtg64ZP1H8vjzuXI6LOQBdw0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Tokarev , Mikulas Patocka , Mike Snitzer Subject: [PATCH 4.9 13/36] dm snapshot: fix a crash when an origin has no snapshots Date: Mon, 24 May 2021 17:24:58 +0200 Message-Id: <20210524152324.601677945@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210524152324.158146731@linuxfoundation.org> References: <20210524152324.158146731@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: linux-kernel@vger.kernel.org From: Mikulas Patocka commit 7ee06ddc4038f936b0d4459d37a7d4d844fb03db upstream. If an origin target has no snapshots, o->split_boundary is set to 0. This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split(). Fix this by initializing chunk_size, and in turn split_boundary, to rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits into "unsigned" type. Reported-by: Michael Tokarev Tested-by: Michael Tokarev Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-snap.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -788,12 +788,11 @@ static int dm_add_exception(void *contex static uint32_t __minimum_chunk_size(struct origin *o) { struct dm_snapshot *snap; - unsigned chunk_size = 0; + unsigned chunk_size = rounddown_pow_of_two(UINT_MAX); if (o) list_for_each_entry(snap, &o->snapshots, list) - chunk_size = min_not_zero(chunk_size, - snap->store->chunk_size); + chunk_size = min(chunk_size, snap->store->chunk_size); return (uint32_t) chunk_size; }