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, URIBL_BLOCKED,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 DFC81C47082 for ; Mon, 31 May 2021 13:39:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B75B861970 for ; Mon, 31 May 2021 13:39:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232285AbhEaNlC (ORCPT ); Mon, 31 May 2021 09:41:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:60152 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232294AbhEaN2E (ORCPT ); Mon, 31 May 2021 09:28:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2615561376; Mon, 31 May 2021 13:22:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1622467324; bh=oRToud7KoChH4nC6fVZXtwAHXTLxa9slLHXrdvWlHGY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=alpzgHdRKSzX96djwcXPGKg5PvK7DeEphiTG/qAq5+wxq/G1/5/u3NmGSkAAwf32J tkf9F0jiM8IZkVZ02rW6I5rtl+weo5xdU/9Rwcfkr00ZjbAG0We0q6+phgQt1RAj/h K0ybCjn+U5/X+I0+DKVjBKW5H77tCDI5ca0bkYz0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Mike Snitzer Subject: [PATCH 4.19 022/116] dm snapshot: properly fix a crash when an origin has no snapshots Date: Mon, 31 May 2021 15:13:18 +0200 Message-Id: <20210531130640.904356684@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531130640.131924542@linuxfoundation.org> References: <20210531130640.131924542@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 7e768532b2396bcb7fbf6f82384b85c0f1d2f197 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. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-snap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -794,7 +794,7 @@ 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)