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=-0.3 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 5A5F5C433E0 for ; Tue, 9 Jun 2020 16:40:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 361562078C for ; Tue, 9 Jun 2020 16:40:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nFSMz8N4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731168AbgFIQkL (ORCPT ); Tue, 9 Jun 2020 12:40:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731074AbgFIQkK (ORCPT ); Tue, 9 Jun 2020 12:40:10 -0400 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97FD3C05BD1E; Tue, 9 Jun 2020 09:40:08 -0700 (PDT) Received: by mail-wm1-x342.google.com with SMTP id u26so2720514wmn.1; Tue, 09 Jun 2020 09:40:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:user-agent:in-reply-to:references:mime-version :content-transfer-encoding:subject:to:cc:from:message-id; bh=7Y2ExY85BoPcedn5x6S+ytoOXLcWpABh59ie+XkypSE=; b=nFSMz8N49ggw5MrKrz8g8uHEyHih78bK1Js/RnT8JimC+Fk4PuQqv96QldQ19q9ADH hzKLxDLVb1viYVoYf25mzUkb+XYvBuw8yTlyj6p5au5dLXMxNcDJCvqp4Jj3Jikn8xgv VvH7O7WZtSKg31WbucAhzlYkkUYxZ+fx1QCJK7+SPW5enr0R4FLaypU3fmTQR3UTzeLB fAN4PcVpqfrXGBswNRJvW4cBCOOsz4fhGW8Tm11KpqejoBgju5JH/yqRJmBYzmuVBs57 W4ROQ63G6KgPUthUSwzRKZj6TUcbc7176ko9eCjaR3CMtGkKRmkeptehWxvFPCdb5Nw0 rdJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:user-agent:in-reply-to:references :mime-version:content-transfer-encoding:subject:to:cc:from :message-id; bh=7Y2ExY85BoPcedn5x6S+ytoOXLcWpABh59ie+XkypSE=; b=QsVoj/nbDx8HjA40YoiwWsprm1EKA78sXrqOeHORHFov05fZ7kRgSWqFsy7ENsPfXG c9JkE6e2Ku9Gub+Vp6zu8x9jhlpYJegQ6wDkY5lqW4wvSe2nBClEdv/bdEg/O9tjiTki 4M55feRlTkoIUAeZxTreJP1oUKgHS2a228KJtMxB62OsUgTuG5IeE9ezjgaNm9e0DyVT Uc9aEYvtZMBTXAHrYvG4XURKda2hYUK6MEFIuMopGeJGKdi8Qj+hdrxCFHfhg3I10g1F M6MFNotJ4mRQKYjU5KoqiQBB+ntYO6WWefoK2e+WdfJeaO4ziI0CJDesCWAQPYjEYr5V YDtQ== X-Gm-Message-State: AOAM533weyCtKeWXhlRziKHsDpF4jJAEl1gVvYMbN9rjQ7i/ZPSP+ySN kYqDAfv0VsirCo4LuC8w2xY= X-Google-Smtp-Source: ABdhPJx66+0aIpQmFRhtjz67aBZc3TeSJXFEsU0xG2C4YryZonJ99z543J+Oj+VxfkEl4HJFaceMLg== X-Received: by 2002:a1c:bd86:: with SMTP id n128mr5209884wmf.5.1591720807292; Tue, 09 Jun 2020 09:40:07 -0700 (PDT) Received: from [192.168.68.104] ([89.237.74.3]) by smtp.gmail.com with ESMTPSA id z2sm3872754wrs.87.2020.06.09.09.40.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Jun 2020 09:40:06 -0700 (PDT) Date: Tue, 09 Jun 2020 19:40:03 +0300 User-Agent: K-9 Mail for Android In-Reply-To: References: <6d4c92b28c54d8ca687c29043562de943a373547.1587675252.git.zanussi@kernel.org> <20200609154741.5kesuvl7txz4s3yu@linutronix.de> <20200609163446.efp76qbjzkbtl7nk@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH RT 1/2] tasklet: Address a race resulting in double-enqueue To: Sebastian Andrzej Siewior , Tom Zanussi CC: LKML , linux-rt-users , Steven Rostedt , Thomas Gleixner , Carsten Emde , John Kacur , Daniel Wagner , Clark Williams , Zhang Xiao From: Ramon Fried Message-ID: <34E6C220-A85B-4296-AB8E-62DE6D9DC561@gmail.com> Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On June 9, 2020 7:37:31 PM GMT+03:00, Ramon Fried wrote: > > >On June 9, 2020 7:34:46 PM GMT+03:00, Sebastian Andrzej Siewior > wrote: >>On 2020-06-09 11:17:53 [-0500], Tom Zanussi wrote: >>> Hi Sebastian, >>Hi Tom, >> >>> I did find a problem with the patch when configured as !SMP since in >>> that case the RUN flag is never set (will send a patch for that >>> shortly), but that wouldn't be the case here=2E >> >>How? >> >>| #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL) >>| static inline int tasklet_trylock(struct tasklet_struct *t) >>| { >>| return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state); >>| } >> >>I can't tell from the backtrace if he runs with RT or without but I >>assumed RT=2E But yes, for !SMP && !RT it would explain it=2E >PREEMT_FULL is enabled=2E=20 >I'm working on getting symbols for this trace, this is a crash kernel >so everything is stripped naked=2E=20 >Thanks, Ramon Correction=2E normal kernel is running with RT enabled, crash kernel witho= ut=2E=20 >> >>> It would help to be able to reproduce it, but I haven't been able to >>> yet=2E >>>=20 >>> Tom >>>=20 >>Sebastian --=20 Sent from my Android device with K-9 Mail=2E Please excuse my brevity=2E