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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 09178C4363A for ; Mon, 26 Oct 2020 23:51:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9644217A0 for ; Mon, 26 Oct 2020 23:51:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603756300; bh=Iv6oWJLm2ZeV/TBAkasOqZMrTumMK7Ca24ww5LvigYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FMTDVg8N2DVXnFSXK65GnnyIFlpR8b6b1Z6Px/TjlMISPTkkj655itaSVRUViPswX K4V4Kk1hfbiQ4zJ6R7S+2TaOWX/qPIsvvhfdoqZv4b7URLXBZfCIXH3ItYk3TP0IBH ONZUmra4Fm54t4DHU/pwyL1JCxrRGTnhxOgmp0gk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409484AbgJZXvi (ORCPT ); Mon, 26 Oct 2020 19:51:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:51686 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409344AbgJZXvO (ORCPT ); Mon, 26 Oct 2020 19:51:14 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DF35121BE5; Mon, 26 Oct 2020 23:51:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603756273; bh=Iv6oWJLm2ZeV/TBAkasOqZMrTumMK7Ca24ww5LvigYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IL7p3mWhez48DCins3LAInHKlV8JK36/+HkHSFVB5k+zSHp6Gmbg4xuX7ZXfnKJOn MVFGYvI2wBELq1fSKoIa+Cc8aE6zOB2AFMUwoNdnydtN9ZI+HO3d8jjbnD+u4LoYel uYEV4BUBA9AReWjwuHaxMdoaJDjjufrpqKThYhNE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zhao Heming , Song Liu , Sasha Levin , linux-raid@vger.kernel.org Subject: [PATCH AUTOSEL 5.9 105/147] md/bitmap: md_bitmap_get_counter returns wrong blocks Date: Mon, 26 Oct 2020 19:48:23 -0400 Message-Id: <20201026234905.1022767-105-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org> References: <20201026234905.1022767-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 b10c51988c8ee..4894c107f72ce 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -1367,7 +1367,7 @@ __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)); -- 2.25.1