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=-10.1 required=3.0 tests=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 964FBC433E1 for ; Mon, 29 Jun 2020 21:52:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 741E620760 for ; Mon, 29 Jun 2020 21:52:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593467522; bh=VK3L9BGAbCNv1q6ujaJ7mqqUR7iptXCtRvdtc56LAmU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=z8rU+th02RWKG8Fyv9zmWpgQlBeFlnvn92nhqPIFATQ38a7/at63YB1sxlOQOwldE oXbrMGnBEVU+nVroqHG5vdPrTN05lMnvpjXkcZvXuzql5VZWFqXovw3UoLJqHUZ3Pn 9whZ5CMGkx0YcqlLpJIA86EWGviu81zyV75sZMbc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404586AbgF2VwB (ORCPT ); Mon, 29 Jun 2020 17:52:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:56790 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726669AbgF2Sfk (ORCPT ); Mon, 29 Jun 2020 14:35:40 -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 BD2C424795; Mon, 29 Jun 2020 15:21:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593444103; bh=VK3L9BGAbCNv1q6ujaJ7mqqUR7iptXCtRvdtc56LAmU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mOdaz3jOqaAD9paXt9eHzDw5YMZ0hjvMG6BGQF80eD/zTNI9HTgjFJjArFdbGQKWH r4jtszacwyiA9yhRsM4dKgOpGVnD88q88pxh+BdW6Y3dx+GOpWLdMr3iuhenPQLpye 1z8U8QEWvuptV3+8ZmZdj5fpOsnnJbzIyYGlvqQw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Gao Xiang , Hongyu Jin , Chao Yu , Greg Kroah-Hartman Subject: [PATCH 5.7 214/265] erofs: fix partially uninitialized misuse in z_erofs_onlinepage_fixup Date: Mon, 29 Jun 2020 11:17:27 -0400 Message-Id: <20200629151818.2493727-215-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629151818.2493727-1-sashal@kernel.org> References: <20200629151818.2493727-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.7.7-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.7.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.7.7-rc1 X-KernelTest-Deadline: 2020-07-01T15:14+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Gao Xiang commit 3c597282887fd55181578996dca52ce697d985a5 upstream. Hongyu reported "id != index" in z_erofs_onlinepage_fixup() with specific aarch64 environment easily, which wasn't shown before. After digging into that, I found that high 32 bits of page->private was set to 0xaaaaaaaa rather than 0 (due to z_erofs_onlinepage_init behavior with specific compiler options). Actually we only use low 32 bits to keep the page information since page->private is only 4 bytes on most 32-bit platforms. However z_erofs_onlinepage_fixup() uses the upper 32 bits by mistake. Let's fix it now. Reported-and-tested-by: Hongyu Jin Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support") Cc: # 4.19+ Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20200618234349.22553-1-hsiangkao@aol.com Signed-off-by: Gao Xiang Signed-off-by: Greg Kroah-Hartman --- fs/erofs/zdata.h | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h index 7824f5563a552..9b66c28b3ae9d 100644 --- a/fs/erofs/zdata.h +++ b/fs/erofs/zdata.h @@ -144,22 +144,22 @@ static inline void z_erofs_onlinepage_init(struct page *page) static inline void z_erofs_onlinepage_fixup(struct page *page, uintptr_t index, bool down) { - unsigned long *p, o, v, id; -repeat: - p = &page_private(page); - o = READ_ONCE(*p); + union z_erofs_onlinepage_converter u = { .v = &page_private(page) }; + int orig, orig_index, val; - id = o >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT; - if (id) { +repeat: + orig = atomic_read(u.o); + orig_index = orig >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT; + if (orig_index) { if (!index) return; - DBG_BUGON(id != index); + DBG_BUGON(orig_index != index); } - v = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) | - ((o & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down); - if (cmpxchg(p, o, v) != o) + val = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) | + ((orig & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down); + if (atomic_cmpxchg(u.o, orig, val) != orig) goto repeat; } -- 2.25.1