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=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 4DF9BC433FF for ; Mon, 29 Jul 2019 19:53:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2095E204EC for ; Mon, 29 Jul 2019 19:53:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564430032; bh=xB2H3tfFN4AhLC7vXs7vXxb6XWm8rStXOPLz45k1tQQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1307TyWPVYpceD21B3TkNydno417yGvUzJxvGDn4Ec8ZZVZ9sOQo8Qt6jX7TGQkJK At1iY7k2E/gn7W8K/+ZHHm9PtUgMNYE/WXVSOOP8Z3EEQcgetr1WrWpeba13B71Rg7 GKGTLN6BZNHBOAjjq8NSrzvOmwRNwu+BpH4Kzp14= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390926AbfG2Txu (ORCPT ); Mon, 29 Jul 2019 15:53:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:45432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403978AbfG2TxP (ORCPT ); Mon, 29 Jul 2019 15:53:15 -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 1617221655; Mon, 29 Jul 2019 19:53:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429994; bh=xB2H3tfFN4AhLC7vXs7vXxb6XWm8rStXOPLz45k1tQQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1FOxChOken1tTEXu4CLDueTIJMxgl9EDIOK70CvRTwUvFbqd1Wp4Dw9iveITW43Em RmyJ6/mmn7UC/ALRHXq4KwOITqQwlRu/077s99+RAIJ6qwa/EcMwnoMbDyeW6cfLN6 fp7P9uJl2VVUpKUTT0LkoYUFTelyFZyH7r/qe2QY= 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 5.2 155/215] memcg, fsnotify: no oom-kill for remote memcg charging Date: Mon, 29 Jul 2019 21:22:31 +0200 Message-Id: <20190729190806.652021662@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190739.971253303@linuxfoundation.org> References: <20190729190739.971253303@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 b428c295d13f..5778d1347b35 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -288,10 +288,13 @@ struct fanotify_event *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 2fda08b2b885..d510223d302c 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -90,9 +90,13 @@ 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