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 DF9ECC433E0 for ; Tue, 9 Jun 2020 16:38:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE6652078D for ; Tue, 9 Jun 2020 16:38:44 +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="p2vDHKH+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731112AbgFIQij (ORCPT ); Tue, 9 Jun 2020 12:38:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727820AbgFIQii (ORCPT ); Tue, 9 Jun 2020 12:38:38 -0400 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96DD7C05BD1E; Tue, 9 Jun 2020 09:38:37 -0700 (PDT) Received: by mail-wr1-x444.google.com with SMTP id j10so22054654wrw.8; Tue, 09 Jun 2020 09:38:37 -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=JGOr7cNh6uCeD4dtTcDluZBxMbP7WaDzdeSNEuXTGcU=; b=p2vDHKH+IxUEftaejbslDeV11CmtoMQVS1oa3R39vPrvYVcrxIfLcqo227SnbF0pGR bIwmkyvu3Azig75yT0F8Zt3tWOP8SDTGVM8tsyWmrRdYVijWjpJlzMsnH6T1PH3JP/T+ T7yqoOO9AcUx7iIwcTWOX87rmVkGLAQQdzJhlSCx+emet9VAinRyVJaLvhWBPDX1HR5B n8lEWOMBsFbdWaXohWbr8GRgoneve4gEDrqNgUD3Cw++Ao4HoYXA/Q4p+8i69k2i54bS rfCi6jNtnb+5ADCCimJZ/cOo4pMK15VQ5zbz6U92DpZfxbaBcRj+/3LzgJBu1HKXFlnH A0bg== 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=JGOr7cNh6uCeD4dtTcDluZBxMbP7WaDzdeSNEuXTGcU=; b=BbeUsyqM3jkjs4FVmzBVIuqq/lKdEaSkymStVIVaHET6D1dwp04gulLYJuetdo1aRz qnXpembuauPYmT+y38FuT/ciJobXptcDS5LnuMWx14Tn6HD7Z/QqPfBkDbAEaPGKHhCH VOgZxdJA7ICxG1N/cOQP29J5SNm2cV96XSkVYuzelgoR9w+L4+hgYC8414JmuD5/Xzxq NdKaC/BiMVgw1fAWah+CVdFQMdL+n8XOwzyJMtCTyeZHxKLT//T2SvTk/Opq228ML8i0 d7j8a11sNr6dKsioMyHn0/9F4fChPCTfncy16SZcTMBOgPv2km4n7eFjLXb5yH51fGvB ZjIg== X-Gm-Message-State: AOAM531Quy9o+MjpUruz+tv1QlTKYXF5wknNvTRU1Kp74nyQi7a5jrQy d+u27ZA9hrY6iVlX3tsqTsLTAPg7/uc= X-Google-Smtp-Source: ABdhPJwyATQekg8AU8SwKm3IdsP31GHM3iVGFzK0iWxf85tYd1O5Jm98/uYV/IIg6qE7kp+HkZzWKA== X-Received: by 2002:adf:bb02:: with SMTP id r2mr5676730wrg.143.1591720716302; Tue, 09 Jun 2020 09:38:36 -0700 (PDT) Received: from [192.168.68.104] ([89.237.74.3]) by smtp.gmail.com with ESMTPSA id r5sm4180693wrq.0.2020.06.09.09.38.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Jun 2020 09:38:35 -0700 (PDT) Date: Tue, 09 Jun 2020 19:37:31 +0300 User-Agent: K-9 Mail for Android In-Reply-To: <20200609163446.efp76qbjzkbtl7nk@linutronix.de> 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: 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 7:34:46 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 e= verything is stripped naked=2E=20 Thanks, Ramon > >> 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