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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 B64DDC432C3 for ; Tue, 3 Dec 2019 22:40:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A93A206EC for ; Tue, 3 Dec 2019 22:40:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575412858; bh=uAgnL+AGiaxwbGNAJ3Nh9nL+IzPCCFmp/0KO5eh3YxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=w6eD4nW+7T9nUW0WYMijXdwgqVZNhtvTVDHpy/GnJx/ETXQk/BJUADwrg3LRW6uDL hugE8h0qe/fQWVTUbcD1yDmlf9ZpYll9dBkbAB+P+jdvcjLB7ubp6Za92U5vY5TjWb 6bHGAc2MsgkAKM7u7bJmJq6i43Kxx7ZIPb7cbpR0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727669AbfLCWk5 (ORCPT ); Tue, 3 Dec 2019 17:40:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:54566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728145AbfLCWkt (ORCPT ); Tue, 3 Dec 2019 17:40:49 -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 D0E7D2073C; Tue, 3 Dec 2019 22:40:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575412849; bh=uAgnL+AGiaxwbGNAJ3Nh9nL+IzPCCFmp/0KO5eh3YxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cw3pDbfv7AYlvpxKmaYlPERUyEYBdCpfntoPBFE0u0/8uqopXjVVn2KUAEBwcOR39 O7fL6+yiNW7inuqPqnnjkWKmNZb9Cnkbl0R0pokStG+XRv1kiEwc0Im7FfRt7BTgIe 6mpnqPkG4alEqugY1eJiQcR1RB4+4c9vAAwO650k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kent Overstreet , "Matthew Wilcox (Oracle)" , Sasha Levin Subject: [PATCH 5.3 004/135] XArray: Fix xas_next() with a single entry at 0 Date: Tue, 3 Dec 2019 23:34:04 +0100 Message-Id: <20191203213006.620763007@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191203213005.828543156@linuxfoundation.org> References: <20191203213005.828543156@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) [ Upstream commit 91abab83839aa2eba073e4a63c729832fdb27ea1 ] If there is only a single entry at 0, the first time we call xas_next(), we return the entry. Unfortunately, all subsequent times we call xas_next(), we also return the entry at 0 instead of noticing that the xa_index is now greater than zero. This broke find_get_pages_contig(). Fixes: 64d3e9a9e0cc ("xarray: Step through an XArray") Reported-by: Kent Overstreet Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Sasha Levin --- lib/test_xarray.c | 24 ++++++++++++++++++++++++ lib/xarray.c | 4 ++++ 2 files changed, 28 insertions(+) diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 9d631a7b6a705..7df4f7f395bf2 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -1110,6 +1110,28 @@ static noinline void check_find_entry(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_move_tiny(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + + XA_BUG_ON(xa, !xa_empty(xa)); + rcu_read_lock(); + XA_BUG_ON(xa, xas_next(&xas) != NULL); + XA_BUG_ON(xa, xas_next(&xas) != NULL); + rcu_read_unlock(); + xa_store_index(xa, 0, GFP_KERNEL); + rcu_read_lock(); + xas_set(&xas, 0); + XA_BUG_ON(xa, xas_next(&xas) != xa_mk_index(0)); + XA_BUG_ON(xa, xas_next(&xas) != NULL); + xas_set(&xas, 0); + XA_BUG_ON(xa, xas_prev(&xas) != xa_mk_index(0)); + XA_BUG_ON(xa, xas_prev(&xas) != NULL); + rcu_read_unlock(); + xa_erase_index(xa, 0); + XA_BUG_ON(xa, !xa_empty(xa)); +} + static noinline void check_move_small(struct xarray *xa, unsigned long idx) { XA_STATE(xas, xa, 0); @@ -1217,6 +1239,8 @@ static noinline void check_move(struct xarray *xa) xa_destroy(xa); + check_move_tiny(xa); + for (i = 0; i < 16; i++) check_move_small(xa, 1UL << i); diff --git a/lib/xarray.c b/lib/xarray.c index 446b956c91888..1237c213f52bc 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -994,6 +994,8 @@ void *__xas_prev(struct xa_state *xas) if (!xas_frozen(xas->xa_node)) xas->xa_index--; + if (!xas->xa_node) + return set_bounds(xas); if (xas_not_node(xas->xa_node)) return xas_load(xas); @@ -1031,6 +1033,8 @@ void *__xas_next(struct xa_state *xas) if (!xas_frozen(xas->xa_node)) xas->xa_index++; + if (!xas->xa_node) + return set_bounds(xas); if (xas_not_node(xas->xa_node)) return xas_load(xas); -- 2.20.1