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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 26A54C7618E for ; Mon, 29 Jul 2019 19:43:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE6DD217D7 for ; Mon, 29 Jul 2019 19:43:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429408; bh=EyK6gRJlxAvJzXu89B1/5FdgCOahdnNn1sjhMN82MkY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=r57CpmqdndFsXFlf7oKt/4MDHbglhbNc63QGXv17Koxeo1aT8+QsHR0FP68zumJZd fuUhkjSCMLUkSY/Kb/yIfRL601C2oZ6TCPOJ4sEkGycQsy85zOdxbxk7RnU818VSDP bM7jHc8CDnqpjwrjA7B+J+5tneB4uGmp4QC/LCK4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389649AbfG2Tn0 (ORCPT ); Mon, 29 Jul 2019 15:43:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:59632 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389639AbfG2TnY (ORCPT ); Mon, 29 Jul 2019 15:43:24 -0400 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 BE31A2054F; Mon, 29 Jul 2019 19:43:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429403; bh=EyK6gRJlxAvJzXu89B1/5FdgCOahdnNn1sjhMN82MkY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hfXjZlv35bc7R72ujLkIBP6YZLOmMUP+xlGsa6pKVWaDCcAGUIb99OoyOz5EA4bMH m8E/txlplzLfig+DOj79PM2Q0smmK1JZ7Vx+gpkltTGO+aXo0zsl0kL5xxYSyfo38q Qrb9y8FzETsKPplttIMRk2n6Jun/MSGQGBxZkDvU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Shakeel Butt , Roman Gushchin , Jan Kara , Johannes Weiner , Vladimir Davydov , Michal Hocko , Amir Goldstein , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.19 087/113] memcg, fsnotify: no oom-kill for remote memcg charging Date: Mon, 29 Jul 2019 21:22:54 +0200 Message-Id: <20190729190716.336041721@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190655.455345569@linuxfoundation.org> References: <20190729190655.455345569@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 [ Upstream commit ec165450968b26298bd1c373de37b0ab6d826b33 ] Commit d46eb14b735b ("fs: fsnotify: account fsnotify metadata to kmemcg") added remote memcg charging for fanotify and inotify event objects. The aim was to charge the memory to the listener who is interested in the events but without triggering the OOM killer. Otherwise there would be security concerns for the listener. At the time, oom-kill trigger was not in the charging path. A parallel work added the oom-kill back to charging path i.e. commit 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the charge path"). So to not trigger oom-killer in the remote memcg, explicitly add __GFP_RETRY_MAYFAIL to the fanotigy and inotify event allocations. Link: http://lkml.kernel.org/r/20190514212259.156585-2-shakeelb@google.com Signed-off-by: Shakeel Butt Reviewed-by: Roman Gushchin Acked-by: Jan Kara Cc: Johannes Weiner Cc: Vladimir Davydov Cc: Michal Hocko Cc: Amir Goldstein Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/notify/fanotify/fanotify.c | 5 ++++- fs/notify/inotify/inotify_fsnotify.c | 8 ++++++-- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 29dee9630eec..a18b8d7a3075 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -148,10 +148,13 @@ struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group, /* * For queues with unlimited length lost events are not expected and * can possibly have security implications. Avoid losing events when - * memory is short. + * memory is short. For the limited size queues, avoid OOM killer in the + * target monitoring memcg as it may have security repercussion. */ if (group->max_events == UINT_MAX) gfp |= __GFP_NOFAIL; + else + gfp |= __GFP_RETRY_MAYFAIL; /* Whoever is interested in the event, pays for the allocation. */ memalloc_use_memcg(group->memcg); diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index f4184b4f3815..16b8702af0e7 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -99,9 +99,13 @@ int inotify_handle_event(struct fsnotify_group *group, i_mark = container_of(inode_mark, struct inotify_inode_mark, fsn_mark); - /* Whoever is interested in the event, pays for the allocation. */ + /* + * Whoever is interested in the event, pays for the allocation. Do not + * trigger OOM killer in the target monitoring memcg as it may have + * security repercussion. + */ memalloc_use_memcg(group->memcg); - event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT); + event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); memalloc_unuse_memcg(); if (unlikely(!event)) { -- 2.20.1