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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19509C001B2 for ; Mon, 19 Dec 2022 22:09:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232710AbiLSWJW (ORCPT ); Mon, 19 Dec 2022 17:09:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232556AbiLSWJB (ORCPT ); Mon, 19 Dec 2022 17:09:01 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01856164A8; Mon, 19 Dec 2022 14:06:33 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F1951B80E48; Mon, 19 Dec 2022 22:05:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88993C433F0; Mon, 19 Dec 2022 22:05:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1671487550; bh=A4qHpnyuxFin9gSIGPKBtc3arPoWOENwBvggAh4TlFo=; h=Date:To:From:Subject:From; b=pmesh8zowd9q2R8VxXCKPrFYB9Al/RGyMOfXCxd0y/z0mnt9tlJ/+g8DJCmcuEXsX XZV5pXtP3iWKd2VgOPvCxT29nwUebUNDA44VuLHYPLO0qarSllFghQQJgoDFKbDK7+ ciWtJe57JDCNNlRo6zRVqUDKrOiHwuk/lQ522fPU= Date: Mon, 19 Dec 2022 14:05:49 -0800 To: mm-commits@vger.kernel.org, usama.anjum@collabora.com, stable@vger.kernel.org, rppt@kernel.org, Liam.Howlett@oracle.com, avagin@gmail.com, liam.howlett@oracle.com, akpm@linux-foundation.org From: Andrew Morton Subject: + maple_tree-fix-mas_spanning_rebalance-on-insufficient-data.patch added to mm-hotfixes-unstable branch Message-Id: <20221219220550.88993C433F0@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: maple_tree: fix mas_spanning_rebalance() on insufficient data has been added to the -mm mm-hotfixes-unstable branch. Its filename is maple_tree-fix-mas_spanning_rebalance-on-insufficient-data.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-fix-mas_spanning_rebalance-on-insufficient-data.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Liam Howlett Subject: maple_tree: fix mas_spanning_rebalance() on insufficient data Date: Mon, 19 Dec 2022 16:20:15 +0000 Mike Rapoport contacted me off-list with a regression in running criu. Periodic tests fail with an RCU stall during execution. Although rare, it is possible to hit this with other uses so this patch should be backported to fix the regression. This patchset adds the fix and a test case to the maple tree test suite. This patch (of 2): An insufficient node was causing an out-of-bounds access on the node in mas_leaf_max_gap(). The cause was the faulty detection of the new node being a root node when overwriting many entries at the end of the tree. Fix the detection of a new root and ensure there is sufficient data prior to entering the spanning rebalance loop. Link: https://lkml.kernel.org/r/20221219161922.2708732-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20221219161922.2708732-2-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Reported-by: Mike Rapoport Tested-by: Mike Rapoport Cc: Andrei Vagin Cc: Mike Rapoport Cc: Muhammad Usama Anjum Cc: Signed-off-by: Andrew Morton --- lib/maple_tree.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/lib/maple_tree.c~maple_tree-fix-mas_spanning_rebalance-on-insufficient-data +++ a/lib/maple_tree.c @@ -2994,7 +2994,9 @@ static int mas_spanning_rebalance(struct mast->free = &free; mast->destroy = &destroy; l_mas.node = r_mas.node = m_mas.node = MAS_NONE; - if (!(mast->orig_l->min && mast->orig_r->max == ULONG_MAX) && + + /* Check if this is not root and has sufficient data. */ + if (((mast->orig_l->min != 0) || (mast->orig_r->max != ULONG_MAX)) && unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type])) mast_spanning_rebalance(mast); _ Patches currently in -mm which might be from liam.howlett@oracle.com are maple_tree-fix-mas_spanning_rebalance-on-insufficient-data.patch test_maple_tree-add-test-for-mas_spanning_rebalance-on-insufficient-data.patch