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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 EE67CC4724B for ; Mon, 24 May 2021 15:54:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEC486109F for ; Mon, 24 May 2021 15:54:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235285AbhEXP4M (ORCPT ); Mon, 24 May 2021 11:56:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:33936 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234091AbhEXPs3 (ORCPT ); Mon, 24 May 2021 11:48:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 220606157F; Mon, 24 May 2021 15:37:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621870649; bh=3tr2OMRnQcEEYAL6cEE519vtoioTcnPkV1HS//zF48Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2Wehs7P9f1T00R5ylYFg3QEzxi9yyR+2HfcjnzL6cfk1snv4goanNYExZC0lCq9y4 mWGmVuRw7rIY/uP/5gLw/EF9a2vNxwAC3w/KttiIN7FvOzNgncflQg88I0IhHrbiHE en+FHtrNzswfXJJoEg8IfuWrocacflGfQxTrOPOo= 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 5.4 42/71] dm snapshot: fix a crash when an origin has no snapshots Date: Mon, 24 May 2021 17:25:48 +0200 Message-Id: <20210524152327.835078212@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210524152326.447759938@linuxfoundation.org> References: <20210524152326.447759938@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 @@ -854,12 +854,11 @@ 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; }