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=-7.3 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,URIBL_BLOCKED,URIBL_DBL_ABUSE_MALW, 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 CB26BC35247 for ; Mon, 3 Feb 2020 16:40:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F46E2082E for ; Mon, 3 Feb 2020 16:40:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580748014; bh=MQloD+ljaY++Y/2nGPXHMv5VcpK5swuR/ik+qbYnln4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=P5MQP2bckyhc3M9MuabiY8qAmUg4zMmMfzd5ktZtW66FR6TEy/bdyclHvvxU2NWQh YQdVqYAH/7toxhAcpj2wBFAGsIxVsyeoS8QfTSEgrH+R4f4weqWD9pP+fv7zFgCdw5 YwxaW8IEeIEF2wZiI9H7zC27lY7HWE0nIR+XAOwc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731495AbgBCQkN (ORCPT ); Mon, 3 Feb 2020 11:40:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:52058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731012AbgBCQgm (ORCPT ); Mon, 3 Feb 2020 11:36:42 -0500 Received: from localhost (unknown [104.132.45.99]) (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 7EB7620721; Mon, 3 Feb 2020 16:36:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580747802; bh=MQloD+ljaY++Y/2nGPXHMv5VcpK5swuR/ik+qbYnln4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dmiCrgmspvxbcC0HXiJ7vpMWfbQ5ZZoKSYy6AjxjgyeXI4LEEWiHoEAt5M/vG0Thu VVllUPbpuB7NA9uAEPKW3rcnBdLjNB10Iu8Uvqw6UBmEKRPe3c7MpZR23e7Rq3tJI0 Wi9vjFyTcoksKNDtasZ0JrICZ4wSieTWjtfh0RdM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Matthew Wilcox (Oracle)" , Sasha Levin Subject: [PATCH 5.4 59/90] XArray: Fix xas_pause at ULONG_MAX Date: Mon, 3 Feb 2020 16:20:02 +0000 Message-Id: <20200203161924.828775805@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200203161917.612554987@linuxfoundation.org> References: <20200203161917.612554987@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 82a22311b7a68a78709699dc8c098953b70e4fd2 ] If we were unlucky enough to call xas_pause() when the index was at ULONG_MAX (or a multi-slot entry which ends at ULONG_MAX), we would wrap the index back around to 0 and restart the iteration from the beginning. Use the XAS_BOUNDS state to indicate that we should just stop the iteration. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Sasha Levin --- lib/test_xarray.c | 22 ++++++++++++++++++++++ lib/xarray.c | 8 +++++--- 2 files changed, 27 insertions(+), 3 deletions(-) diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 03c3f42966cec..55c14e8c88591 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -1160,6 +1160,27 @@ static noinline void check_move_tiny(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_move_max(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + + xa_store_index(xa, ULONG_MAX, GFP_KERNEL); + rcu_read_lock(); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX)); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL); + rcu_read_unlock(); + + xas_set(&xas, 0); + rcu_read_lock(); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX)); + xas_pause(&xas); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL); + rcu_read_unlock(); + + xa_erase_index(xa, ULONG_MAX); + XA_BUG_ON(xa, !xa_empty(xa)); +} + static noinline void check_move_small(struct xarray *xa, unsigned long idx) { XA_STATE(xas, xa, 0); @@ -1268,6 +1289,7 @@ static noinline void check_move(struct xarray *xa) xa_destroy(xa); check_move_tiny(xa); + check_move_max(xa); for (i = 0; i < 16; i++) check_move_small(xa, 1UL << i); diff --git a/lib/xarray.c b/lib/xarray.c index 47e17d46e5f85..1d9fab7db8dad 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -968,6 +968,7 @@ void xas_pause(struct xa_state *xas) if (xas_invalid(xas)) return; + xas->xa_node = XAS_RESTART; if (node) { unsigned int offset = xas->xa_offset; while (++offset < XA_CHUNK_SIZE) { @@ -975,10 +976,11 @@ void xas_pause(struct xa_state *xas) break; } xas->xa_index += (offset - xas->xa_offset) << node->shift; + if (xas->xa_index == 0) + xas->xa_node = XAS_BOUNDS; } else { xas->xa_index++; } - xas->xa_node = XAS_RESTART; } EXPORT_SYMBOL_GPL(xas_pause); @@ -1080,7 +1082,7 @@ void *xas_find(struct xa_state *xas, unsigned long max) { void *entry; - if (xas_error(xas)) + if (xas_error(xas) || xas->xa_node == XAS_BOUNDS) return NULL; if (xas->xa_index > max) return set_bounds(xas); @@ -1088,7 +1090,7 @@ void *xas_find(struct xa_state *xas, unsigned long max) if (!xas->xa_node) { xas->xa_index = 1; return set_bounds(xas); - } else if (xas_top(xas->xa_node)) { + } else if (xas->xa_node == XAS_RESTART) { entry = xas_load(xas); if (entry || xas_not_node(xas->xa_node)) return entry; -- 2.20.1