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=-21.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 345A9C432BE for ; Thu, 19 Aug 2021 17:26:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F07C6108B for ; Thu, 19 Aug 2021 17:26:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231137AbhHSR1K (ORCPT ); Thu, 19 Aug 2021 13:27:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:44830 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233320AbhHSR1A (ORCPT ); Thu, 19 Aug 2021 13:27:00 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 56BC46023D; Thu, 19 Aug 2021 17:26:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629393984; bh=8bMRr+3lfqS+WTA5uS17IcE0HsMA5fSxcfqzv64+Qb0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=japYTi3pXOAm+MYDjP5qNag4LYEX/axH5/9smIvPYi/7E+EzQcScMaEvCb3lU3U3Z DU+ow6LmGZUkbxUqkCP7oUnU8CD4mvyTQ0bmcaYw8BT+bp5iPx+UWFOdOSRTQYr9JC Qo0keJI3rjxyS1AMhTATZySI9J67wgScP5TsrIPS9QmawEYmO4RkIW0BME0Z9naapS MjACPVxws/0BnKn2OQu8dksmwpLa2MxiCkaX8SxxdFSUFWk2pJSpyAUK/oK26L1rX2 cg+Ry7A76PhyuyBpV9/z0o9m/imLG23PocyH7FHPJ6k4fRYoN++eFTZjCIwySpvTZk LtiptUaxG7pzA== Date: Thu, 19 Aug 2021 19:26:18 +0200 From: Alexey Gladkov To: "Eric W. Biederman" Cc: "Ma, XinjianX" , "linux-kselftest@vger.kernel.org" , lkp , "akpm@linux-foundation.org" , "axboe@kernel.dk" , "christian.brauner@ubuntu.com" , "containers@lists.linux-foundation.org" , "jannh@google.com" , "keescook@chromium.org" , "kernel-hardening@lists.openwall.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "oleg@redhat.com" , "torvalds@linux-foundation.org" Subject: Re: [PATCH v11 5/9] Reimplement RLIMIT_MSGQUEUE on top of ucounts Message-ID: <20210819172618.qwrrw4m7wt33wfmz@example.org> References: <87a6lgysxp.fsf@disp2133> <20210818131117.x7omzb2wkjq7le3s@example.org> <87o89ttqql.fsf@disp2133> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87o89ttqql.fsf@disp2133> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 19, 2021 at 10:10:26AM -0500, Eric W. Biederman wrote: > Alexey Gladkov writes: > > > On Tue, Aug 17, 2021 at 10:47:14AM -0500, Eric W. Biederman wrote: > >> "Ma, XinjianX" writes: > >> > >> > Hi Alexey, > >> > > >> > When lkp team run kernel selftests, we found after these series of patches, testcase mqueue: mq_perf_tests > >> > in kselftest failed with following message. > >> > >> Which kernel was this run against? > >> > >> Where can the mq_perf_tests that you ran and had problems with be found? > >> > >> During your run were you using user namespaces as part of your test > >> environment? > >> > >> The error message too many files corresponds to the error code EMFILES > >> which is the error code that is returned when the rlimit is reached. > >> > >> One possibility is that your test environment was run in a user > >> namespace and so you wound up limited by rlimit of the user who created > >> the user namespace at the point of user namespace creation. > >> > >> At this point if you can give us enough information to look into this > >> and attempt to reproduce it that would be appreciated. > > > > I was able to reproduce it on master without using user namespace. > > I suspect that the maximum value is not assigned here [1]: > > > > set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, task_rlimit(&init_task, RLIMIT_MSGQUEUE)); > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/fork.c#n832 > > The rlimits for init_task are set to INIT_RLIMITS. > In INIT_RLIMITS RLIMIT_MSGQUEUE is set to MQ_MAX_BYTES > > So that definitely means that as the code is current constructed the > rlimit can not be effectively raised. > > So it looks like we are just silly and preventing the initial rlimits > from being raised. > > So we probably want to do something like: Damn, you are faster than me! :) > diff --git a/kernel/fork.c b/kernel/fork.c > index bc94b2cc5995..557ce0083ba3 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -825,13 +825,13 @@ void __init fork_init(void) > init_task.signal->rlim[RLIMIT_SIGPENDING] = > init_task.signal->rlim[RLIMIT_NPROC]; > > + /* For non-rlimit ucounts make their default limit max_threads/2 */ > for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) > init_user_ns.ucount_max[i] = max_threads/2; > > - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, task_rlimit(&init_task, RLIMIT_NPROC)); > - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, task_rlimit(&init_task, RLIMIT_MSGQUEUE)); > - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, task_rlimit(&init_task, RLIMIT_SIGPENDING)); > - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, task_rlimit(&init_task, RLIMIT_MEMLOCK)); > + /* In init_user_ns default rlimit to be the only limit */ > + for (; i < UCOUNT_COUNTS; i++) > + set_rlimit_ucount_max(&init_user_ns, i, RLIMIT_INFINITY); s/RLIMIT_INFINITY/RLIM_INFINITY/ > > #ifdef CONFIG_VMAP_STACK > cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", > Acked-by: Alexey Gladkov I cannot complete this test on my laptop. On 4Gb, the test ends with oom-killer. But with this patch, the test definitely passes the moment of the previous fall. -- Rgrds, legion