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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 DF5CFC76188 for ; Fri, 19 Jul 2019 04:34:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B92E9206DD for ; Fri, 19 Jul 2019 04:34:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563510852; bh=fyLQrmMQLInm4NczQvVlEaI7afIW3DlZkxyO6PK9s3w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FCwpCwGLl9QaAvggmo+21TopAxV0p7v82rUwgNWvexF1xmoXcbifkXN6YGWQbrhs6 CuBmZsWb4CnBqCMc7MLxSI7Pv08apM5Yc993IXraUQrfhJcV8RXe1dhF/OfaVvU5aN TpDcJ/0oek4cT4S9i+sqCKOunpx++AWlWkoX7UvA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733066AbfGSEeK (ORCPT ); Fri, 19 Jul 2019 00:34:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:33936 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729818AbfGSECH (ORCPT ); Fri, 19 Jul 2019 00:02:07 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EC819218A5; Fri, 19 Jul 2019 04:02:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563508926; bh=fyLQrmMQLInm4NczQvVlEaI7afIW3DlZkxyO6PK9s3w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BsX1gdTY/UQ6NEPWlAoKUPO1Rt+KPhLbRFrHXNFF0STGhvRQr+7yKIBwnqBUy8G98 0r1C71PrvkUurz/2GQomexX5j4xIW+vtK0GZB5uDyu8p9/LcGy0pGoNpZXLd/KO6PT EyYJBFnfyBJPURkbyUqOufpz6X0aSn+fqAIjpNKQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Shakeel Butt , Roman Gushchin , Jan Kara , Johannes Weiner , Vladimir Davydov , Michal Hocko , Amir Goldstein , Andrew Morton , Linus Torvalds , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 5.2 161/171] memcg, fsnotify: no oom-kill for remote memcg charging Date: Thu, 18 Jul 2019 23:56:32 -0400 Message-Id: <20190719035643.14300-161-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190719035643.14300-1-sashal@kernel.org> References: <20190719035643.14300-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Shakeel Butt [ 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