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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 E09F2C433B4 for ; Wed, 31 Mar 2021 22:28:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A5FC60FD9 for ; Wed, 31 Mar 2021 22:28:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231974AbhCaW2S (ORCPT ); Wed, 31 Mar 2021 18:28:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:52774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232493AbhCaW2E (ORCPT ); Wed, 31 Mar 2021 18:28:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8594360FD9; Wed, 31 Mar 2021 22:28:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1617229684; bh=wzX5g2x+u6CtyPQpthcE8Br63vA8ZHEXJp6NRVkca+E=; h=Date:From:To:Subject:From; b=b1TxFl9DT8xd4eJFcHB+uiViHeJ5DcxfTIcH35f2H+806K/UGl6HSRbSn7GNMAyqv eVSD/Goq/6rru7x2Dois+9x8lgjWwsgu7Q6ZWHo1Zyl2OkxY659DVmJtOahCow2xfX DDU+4MBydFQ2/ROHSf9hfZEIJ9BBGCNymp1Q2a0Q= Date: Wed, 31 Mar 2021 15:28:02 -0700 From: akpm@linux-foundation.org To: david@fromorbit.com, guro@fb.com, hannes@cmpxchg.org, hughd@google.com, ktkhai@virtuozzo.com, mhocko@suse.com, mm-commits@vger.kernel.org, oliver.sang@intel.com, shakeelb@google.com, shy828301@gmail.com, vbabka@suse.cz Subject: [withdrawn] mm-vmscan-add-per-memcg-shrinker-nr_deferred-fix.patch removed from -mm tree Message-ID: <20210331222802.S21XiQ2bG%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: vmscan: fix shrinker_rwsem in free_shrinker_info() has been removed from the -mm tree. Its filename was mm-vmscan-add-per-memcg-shrinker-nr_deferred-fix.patch This patch was dropped because it was withdrawn ------------------------------------------------------ From: Hugh Dickins Subject: mm: vmscan: fix shrinker_rwsem in free_shrinker_info() Lockdep warns mm/vmscan.c: suspicious rcu_dereference_protected() usage! when free_shrinker_info() is called from mem_cgroup_css_free(): there it is called with no locking, whereas alloc_shrinker_info() calls it with down_write of shrinker_rwsem - which seems appropriate. Rearrange that so free_shrinker_info() can manage the shrinker_rwsem for itself. Link: https://lkml.kernel.org/r/20210317140615.GB28839@xsang-OptiPlex-9020 Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2103301640240.2584@eggly.anvils Reported-by: kernel test robot Signed-off-by: Hugh Dickins Cc: Yang Shi Cc: Roman Gushchin Cc: Kirill Tkhai Cc: Shakeel Butt Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/vmscan.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/mm/vmscan.c~mm-vmscan-add-per-memcg-shrinker-nr_deferred-fix +++ a/mm/vmscan.c @@ -249,18 +249,20 @@ void free_shrinker_info(struct mem_cgrou struct shrinker_info *info; int nid; + down_write(&shrinker_rwsem); for_each_node(nid) { pn = memcg->nodeinfo[nid]; info = shrinker_info_protected(memcg, nid); kvfree(info); rcu_assign_pointer(pn->shrinker_info, NULL); } + up_write(&shrinker_rwsem); } int alloc_shrinker_info(struct mem_cgroup *memcg) { struct shrinker_info *info; - int nid, size, ret = 0; + int nid, size; int map_size, defer_size = 0; down_write(&shrinker_rwsem); @@ -270,9 +272,9 @@ int alloc_shrinker_info(struct mem_cgrou for_each_node(nid) { info = kvzalloc_node(sizeof(*info) + size, GFP_KERNEL, nid); if (!info) { + up_write(&shrinker_rwsem); free_shrinker_info(memcg); - ret = -ENOMEM; - break; + return -ENOMEM; } info->nr_deferred = (atomic_long_t *)(info + 1); info->map = (void *)info->nr_deferred + defer_size; @@ -280,7 +282,7 @@ int alloc_shrinker_info(struct mem_cgrou } up_write(&shrinker_rwsem); - return ret; + return 0; } static inline bool need_expand(int nr_max) _ Patches currently in -mm which might be from hughd@google.com are mm-restore-node-stat-checking-in-proc-sys-vm-stat_refresh.patch mm-no-more-einval-from-proc-sys-vm-stat_refresh.patch mm-proc-sys-vm-stat_refresh-skip-checking-known-negative-stats.patch mm-proc-sys-vm-stat_refresh-stop-checking-monotonic-numa-stats.patch