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=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 C5FEAC76188 for ; Fri, 19 Jul 2019 04:27:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A037120873 for ; Fri, 19 Jul 2019 04:27:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563510451; bh=mjpXVKodQX07mlOxhWXJOjjSgftRWp5qKcdqRVQpF+c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=l+EC5XjyIW1zdM7omYZWOoP/Cbp+R14sFAGhu/5Z6vGjIjk82EaqnPdCldkm1OpMq 8aPZvk/SdHhFNRNu8NtOOnveBSdP8x7Org+Q/fL22PoamCFC0o0CxDaHqBbx6PiUJL JqVZeg71N+ZQoQR1uA5al/HJ67Nikd9XNamciPfA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733052AbfGSE1a (ORCPT ); Fri, 19 Jul 2019 00:27:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:40372 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729157AbfGSEG4 (ORCPT ); Fri, 19 Jul 2019 00:06:56 -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 30AB6218A6; Fri, 19 Jul 2019 04:06:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563509215; bh=mjpXVKodQX07mlOxhWXJOjjSgftRWp5qKcdqRVQpF+c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Rq++uQhSfs3SRs5LVZs+ZkgCKbxfGxA7mS8hwh0D7/6ErrmhfBh0ZspYZ+hJfrGv3 mIzPq01kInkP6FZKH3GzDXBrEKEpRh5jkaILuLdMWQq6JOCIhaI8VlHz3IO09mjN/Z RJ6ioQ5GqCts683vPRuoq3/YEiSd1QZXMatN7JvQ= 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 5.1 131/141] memcg, fsnotify: no oom-kill for remote memcg charging Date: Fri, 19 Jul 2019 00:02:36 -0400 Message-Id: <20190719040246.15945-131-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190719040246.15945-1-sashal@kernel.org> References: <20190719040246.15945-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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 8c286f8228e5..d5db722ac272 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 ff30abd6a49b..ca1a9dfff0b5 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