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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 A7457C388F7 for ; Tue, 3 Nov 2020 21:06:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CE792236F for ; Tue, 3 Nov 2020 21:06:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604437579; bh=h4131RUf+Q4hXM1qSEf0WumYcMJdY0zfofruLlAEoXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hXRLw66L+lqX3nUoPpzNqqEsBCQVOCcXP3aMl5wmhafeJEh/DQOTVXmCHDJgHU+eC CbW+mY6aV5F5RwNsz3BpsBdRHn5OXAl4ADw8yxY3o/q1kUfcidBi50qa6UH5V8fnmD 71SWVpqBIkMBCp5MrkbMc7NdjCyuYrV12JVvf0bw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388130AbgKCVGQ (ORCPT ); Tue, 3 Nov 2020 16:06:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:45008 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388109AbgKCVGJ (ORCPT ); Tue, 3 Nov 2020 16:06:09 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 29797206B5; Tue, 3 Nov 2020 21:06:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604437568; bh=h4131RUf+Q4hXM1qSEf0WumYcMJdY0zfofruLlAEoXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Pcu+qDB/Tvk0FCVNSfFi2PXPexFk58oAlsxzU+c9GO+Pue7mvWEP6RXy2G6nEbv81 Si+ccu5KE3pgbp6OtI7AXI7Q84kJBQz+EJc+Gp5Ex9pd+dxFYaajkAUaMjPsnpse+7 fLYQWkLlzamEyZG9jiSVIrrJv5oi+rYwF3IiXL80= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhao Heming , Song Liu , Sasha Levin Subject: [PATCH 4.19 094/191] md/bitmap: md_bitmap_get_counter returns wrong blocks Date: Tue, 3 Nov 2020 21:36:26 +0100 Message-Id: <20201103203242.679798798@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203232.656475008@linuxfoundation.org> References: <20201103203232.656475008@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: Zhao Heming [ Upstream commit d837f7277f56e70d82b3a4a037d744854e62f387 ] md_bitmap_get_counter() has code: ``` if (bitmap->bp[page].hijacked || bitmap->bp[page].map == NULL) csize = ((sector_t)1) << (bitmap->chunkshift + PAGE_COUNTER_SHIFT - 1); ``` The minus 1 is wrong, this branch should report 2048 bits of space. With "-1" action, this only report 1024 bit of space. This bug code returns wrong blocks, but it doesn't inflence bitmap logic: 1. Most callers focus this function return value (the counter of offset), not the parameter blocks. 2. The bug is only triggered when hijacked is true or map is NULL. the hijacked true condition is very rare. the "map == null" only true when array is creating or resizing. 3. Even the caller gets wrong blocks, current code makes caller just to call md_bitmap_get_counter() one more time. Signed-off-by: Zhao Heming Signed-off-by: Song Liu Signed-off-by: Sasha Levin --- drivers/md/md-bitmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index fd8607124bdbb..503f5e06fa86f 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -1371,7 +1371,7 @@ __acquires(bitmap->lock) if (bitmap->bp[page].hijacked || bitmap->bp[page].map == NULL) csize = ((sector_t)1) << (bitmap->chunkshift + - PAGE_COUNTER_SHIFT - 1); + PAGE_COUNTER_SHIFT); else csize = ((sector_t)1) << bitmap->chunkshift; *blocks = csize - (offset & (csize - 1)); -- 2.27.0