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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B73B3C433EF for ; Fri, 22 Apr 2022 22:03:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231416AbiDVWGc (ORCPT ); Fri, 22 Apr 2022 18:06:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231322AbiDVWF7 (ORCPT ); Fri, 22 Apr 2022 18:05:59 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB4981F512C for ; Fri, 22 Apr 2022 13:49:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 29564B8325F for ; Fri, 22 Apr 2022 20:20:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B578CC385AC; Fri, 22 Apr 2022 20:20:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1650658847; bh=sjSUAIA9cjXHWV5U/WviL4KaV6WulCbZ6A1nlUXBnq4=; h=Date:To:From:Subject:From; b=sXW8KRtg2FqUV3ScaOVGKos8dx5tnErwLwkM7RDE0vdtILh8UWRBvJDCmtAPoqcpN /v+HYSyF1N9RNrx2qk5+j6sm1PrEGgLEpEo96xZ2EwlZZ6R08dFyIcdb9+kpqmyh5L Te3lZirjXwbFB8pstpcQAkfKpPcisFDfkxtuUOu4= Date: Fri, 22 Apr 2022 13:20:47 -0700 To: mm-commits@vger.kernel.org, tj@kernel.org, shakeelb@google.com, roman.gushchin@linux.dev, mhocko@kernel.org, hannes@cmpxchg.org, void@manifault.com, akpm@linux-foundation.org From: Andrew Morton Subject: + cgroup-removing-racy-check-in-test_memcg_sock.patch added to -mm tree Message-Id: <20220422202047.B578CC385AC@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: cgroup: removing racy check in test_memcg_sock() has been added to the -mm tree. Its filename is cgroup-removing-racy-check-in-test_memcg_sock.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/cgroup-removing-racy-check-in-test_memcg_sock.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/cgroup-removing-racy-check-in-test_memcg_sock.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: David Vernet Subject: cgroup: removing racy check in test_memcg_sock() test_memcg_sock() in the cgroup memcg tests, verifies expected memory accounting for sockets. The test forks a process which functions as a TCP server, and sends large buffers back and forth between itself (as the TCP client) and the forked TCP server. While doing so, it verifies that memory.current and memory.stat.sock look correct. There is currently a check in tcp_client() which asserts memory.current >= memory.stat.sock. This check is racy, as between memory.current and memory.stat.sock being queried, a packet could come in which causes mem_cgroup_charge_skmem() to be invoked. This could cause memory.stat.sock to exceed memory.current. Reversing the order of querying doesn't address the problem either, as memory may be reclaimed between the two calls. Instead, this patch just removes that assertion altogether, and instead relies on the values_close() check that follows to validate the expected accounting. Link: https://lkml.kernel.org/r/20220422155728.3055914-5-void@manifault.com Signed-off-by: David Vernet Cc: Johannes Weiner Cc: Michal Hocko Cc: Roman Gushchin Cc: Shakeel Butt Cc: Tejun Heo Signed-off-by: Andrew Morton --- tools/testing/selftests/cgroup/test_memcontrol.c | 3 --- 1 file changed, 3 deletions(-) --- a/tools/testing/selftests/cgroup/test_memcontrol.c~cgroup-removing-racy-check-in-test_memcg_sock +++ a/tools/testing/selftests/cgroup/test_memcontrol.c @@ -993,9 +993,6 @@ static int tcp_client(const char *cgroup if (current < 0 || sock < 0) goto close_sk; - if (current < sock) - goto close_sk; - if (values_close(current, sock, 10)) { ret = KSFT_PASS; break; _ Patches currently in -mm which might be from void@manifault.com are cgroups-refactor-children-cgroups-in-memcg-tests.patch cgroup-account-for-memory_recursiveprot-in-test_memcg_low.patch cgroup-account-for-memory_localevents-in-test_memcg_oom_group_leaf_events.patch cgroup-removing-racy-check-in-test_memcg_sock.patch cgroup-fix-racy-check-in-alloc_pagecache_max_30m-helper-function.patch