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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 55A48C433ED for ; Wed, 14 Apr 2021 17:59:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2576D61177 for ; Wed, 14 Apr 2021 17:59:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351257AbhDNR76 (ORCPT ); Wed, 14 Apr 2021 13:59:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234303AbhDNR76 (ORCPT ); Wed, 14 Apr 2021 13:59:58 -0400 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E13AC061574 for ; Wed, 14 Apr 2021 10:59:36 -0700 (PDT) Received: by mail-lj1-x236.google.com with SMTP id a1so24259164ljp.2 for ; Wed, 14 Apr 2021 10:59:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=W7HWJZfAqr4Movt5xn3m8CynE2j6l85Xy4oR/SEiJtk=; b=IVbIWvqaFaSytfTGY62MUYs/YMSRgyFy0/nIjTmM/8YgInq8yXXb+zC1QhG5pTEBS7 GCtHZZZBCvAPjiS4ygRdlrJ0crDFycxLGAiru+HfDAgDO6QEZgCHUN3k2l+0/pUbvoGu Upm3uU81sethFLJFIjsQC5oSkI094jvhJ0iXTO0qTiYSnz3G33AiQK28/m245E9GE3gR fPnZL6y5olAX1nqKjqLAr8PZK5KfmI5O96Jku/4kN0WfnaprSwGL2K9Fmdr6iQeQeR6f hbqvIicldBKimLiM8SaEhhljmRjQ323T87kVW6icMH3ObCUajJS6E40sDXqJyCcCdccf kHQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=W7HWJZfAqr4Movt5xn3m8CynE2j6l85Xy4oR/SEiJtk=; b=sWN4DbLalwwz0+6JkohX/NUj/Yppp4kIfaxl3LgeE6mJZSuwvbsD8qVuKJf0OpMPju vSamaSSnWIwtB+3TC1RXmHYgnYIEQIUsI82Phv7zmN1fX9QK1pWmFLDBC+CXEC7VA56W JZXwC9Yjt+CxLnBhAp2dft7/YmQh0B9FnMgShwORRSmHVrhttHPE4sUjOkwX4xSNtLTe /QWdeMqaxRQNOk8AnOSh6/PshV1zPi1guFzX+UweGU8NeVtSUKjaBkF/i18aF3TFxOT/ hwHaM2FHTrAZzgWekzLWOrcGvCaTvtBV+KDuov032PYPEbQoKp3J4FbLV35tf6mCrizc gu6w== X-Gm-Message-State: AOAM5336Skxwt5njPlLakUuyIUAeIPyj+7q78ft3FW0YvDLKnlcJYP2+ oGYYY0pKePVb8ttmM+Wifv+McQ8S1DMZvthgtcw= X-Google-Smtp-Source: ABdhPJyuQCSYELaOFYWQicEr5qSF2ZPK0mdmAUMb53smDwXQKUZdtryz+0i2rADts6MJlLdOy6H1dnqJYfrl8ly55Pc= X-Received: by 2002:a2e:894d:: with SMTP id b13mr16327851ljk.486.1618423175177; Wed, 14 Apr 2021 10:59:35 -0700 (PDT) MIME-Version: 1.0 References: <87blaozi20.fsf@toke.dk> <87im4qo9ey.fsf@toke.dk> <20210414175245.GT4510@paulmck-ThinkPad-P17-Gen-1> In-Reply-To: <20210414175245.GT4510@paulmck-ThinkPad-P17-Gen-1> From: Alexei Starovoitov Date: Wed, 14 Apr 2021 10:59:23 -0700 Message-ID: Subject: Re: Selftest failures related to kern_sync_rcu() To: "Paul E. McKenney" Cc: Andrii Nakryiko , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , bpf Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Apr 14, 2021 at 10:52 AM Paul E. McKenney wrote: > > > > > > if (num_online_cpus() > 1) > > > > > synchronize_rcu(); > > In CONFIG_PREEMPT_NONE=y and CONFIG_PREEMPT_VOLUNTARY=y kernels, this > synchronize_rcu() will be a no-op anyway due to there only being the > one CPU. Or are these failures all happening in CONFIG_PREEMPT=y kernels, > and in tests where preemption could result in the observed failures? > > Could you please send your .config file, or at least the relevant portions > of it? That's my understanding as well. I assumed Toke has preempt=y. Otherwise the whole thing needs to be root caused properly.