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=-4.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_DBL_ABUSE_MALW,USER_AGENT_GIT autolearn=no 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 81C5FC33CB3 for ; Tue, 28 Jan 2020 14:03:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 565B824685 for ; Tue, 28 Jan 2020 14:03:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580220186; bh=9SeEzEL13nTWWwVtaYrsa7o11fBxFK58T2PwnjRlYOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZGySwBMq47G+n4r0bJQC/1h7GWo9REC1Chuv3y5r85ygqrg3I82ZjBDwl/iUkbV5r KcYADg37jDDcQWTfDyGP+hrpaATrI8fDQuzgA+jxMADpVKA2069xkIjGU1x5DvXS8N fJtK+A30Is4AP9IOeSFDI0Uv4EfhgXV6Hsb3UaCY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727795AbgA1ODF (ORCPT ); Tue, 28 Jan 2020 09:03:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:49582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727782AbgA1ODC (ORCPT ); Tue, 28 Jan 2020 09:03:02 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 83612205F4; Tue, 28 Jan 2020 14:03:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580220182; bh=9SeEzEL13nTWWwVtaYrsa7o11fBxFK58T2PwnjRlYOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zm9RXpOPbbyThZxj4+0A9IM9hA8B+VnbckRk/rxQyPPWnIH3pGmLJ/hV0lI2WUJA8 E9iA33J8lJjLAoDeKhNErq+IaTU5eD58+1IWrX/7AoCicGnmgWT4uoGZAk3x8uLa37 3IIp1u3p2tfew14tk0HnSBvXzM6bhqgwuBHFS7RA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Matthew Wilcox (Oracle)" Subject: [PATCH 5.4 050/104] XArray: Fix infinite loop with entry at ULONG_MAX Date: Tue, 28 Jan 2020 15:00:11 +0100 Message-Id: <20200128135824.574648455@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135817.238524998@linuxfoundation.org> References: <20200128135817.238524998@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Matthew Wilcox (Oracle) commit 430f24f94c8a174d411a550d7b5529301922e67a upstream. If there is an entry at ULONG_MAX, xa_for_each() will overflow the 'index + 1' in xa_find_after() and wrap around to 0. Catch this case and terminate the loop by returning NULL. Signed-off-by: Matthew Wilcox (Oracle) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- lib/test_xarray.c | 17 +++++++++++++++++ lib/xarray.c | 3 +++ 2 files changed, 20 insertions(+) --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -1046,11 +1046,28 @@ static noinline void check_find_3(struct xa_destroy(xa); } +static noinline void check_find_4(struct xarray *xa) +{ + unsigned long index = 0; + void *entry; + + xa_store_index(xa, ULONG_MAX, GFP_KERNEL); + + entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT); + XA_BUG_ON(xa, entry != xa_mk_index(ULONG_MAX)); + + entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT); + XA_BUG_ON(xa, entry); + + xa_erase_index(xa, ULONG_MAX); +} + static noinline void check_find(struct xarray *xa) { check_find_1(xa); check_find_2(xa); check_find_3(xa); + check_find_4(xa); check_multi_find(xa); check_multi_find_2(xa); } --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1847,6 +1847,9 @@ void *xa_find_after(struct xarray *xa, u XA_STATE(xas, xa, *indexp + 1); void *entry; + if (xas.xa_index == 0) + return NULL; + rcu_read_lock(); for (;;) { if ((__force unsigned int)filter < XA_MAX_MARKS)