From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C6B333DF; Thu, 3 Jul 2025 01:04:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.190 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751504680; cv=none; b=ho3kH9P9svGTCZzsk/jjTXkTy7wQ9y2PBhnq3mRZ8LKlVcm7vRj26BSI9TCYQ1Yx22HZYX5VpljJHbTe8zIjVx8q1XbcEFHnKToZkwkmhwN/mdlmEq49Zc+Mgj7hbFMt1n73yLpw/rdW016ZxKeNb0DdHO3xwgDDwIxLpUw+u74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751504680; c=relaxed/simple; bh=JlAOZZjzEGS5FPV5Oiqzo/4Njn+txUSWp1s0aZkR5iY=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=R0JiBks/6Vj5enkisqXKnkygWrJMDuxCv2zzchiW7J+/nDz87tUvt7dKhZ24JsUBdr3M+aSZVMkkejka27kR3XseJfAwAkUGi8Vx4XskvAu/W30aq/pdGx7iivR5w87k7LBztjIWovPKDi+FHyS75e7Qv0WA2oxCq+2aUTugmoc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.190 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.44]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4bXdm56rNkz2TSmQ; Thu, 3 Jul 2025 09:02:45 +0800 (CST) Received: from dggemv705-chm.china.huawei.com (unknown [10.3.19.32]) by mail.maildlp.com (Postfix) with ESMTPS id 1A6FA14022E; Thu, 3 Jul 2025 09:04:33 +0800 (CST) Received: from kwepemq500009.china.huawei.com (7.202.195.53) by dggemv705-chm.china.huawei.com (10.3.19.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 3 Jul 2025 09:04:32 +0800 Received: from [10.174.179.5] (10.174.179.5) by kwepemq500009.china.huawei.com (7.202.195.53) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 3 Jul 2025 09:04:31 +0800 Subject: Re: [QUESTION] problems report: rcu_read_unlock_special() called in irq_exit() causes dead loop To: Joel Fernandes , Qi Xi , CC: Joel Fernandes , , Frederic Weisbecker , Boqun Feng , , , , , "Wangshaobo (bobo)" , Xie XiuQi References: <9acd5f9f-6732-7701-6880-4b51190aa070@huawei.com> <3ce6f3ce-5dfb-8c59-cb7b-4619b70f8d25@huawei.com> <20250603185939.GA1109523@joelnvbox> <066e8121-c6c5-48ac-b35a-e6430d986dff@nvidia.com> <09e4d018-3db4-404e-a8f0-041cdee15a62@huawei.com> <279d2f06-d4f7-46e1-9678-999a2d19b710@nvidia.com> <506d8c4e-c317-4c85-9bcf-695596551d28@huawei.com> <166bc5aa-a715-438e-8805-c74c2b5fc83b@nvidia.com> From: Xiongfeng Wang Message-ID: <8f5925c1-9553-63d3-d5a0-387c2395963d@huawei.com> Date: Thu, 3 Jul 2025 09:04:31 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To kwepemq500009.china.huawei.com (7.202.195.53) On 2025/7/3 1:24, Joel Fernandes wrote: > > > On 7/2/2025 6:59 AM, Joel Fernandes wrote: >> >> >> On 7/2/2025 5:14 AM, Qi Xi wrote: >>> Hi Joel, >>> >>> After applying the 2 patches, the problem still exists. Compared to the previous >>> fixes which did solve the problem, the difference is ct_in_irq() in the first >>> patch. >>> >>> I am wondering why "nesting != CT_NESTING_IRQ_NONIDLE" is added? >>> >>> >>> (previous fix: problem is solved) >>> >>> +bool ct_in_irq(void) >>> +{ >>> +    return ct_nmi_nesting() != 0; >>> +} >>> >>> (current fix: problem still exists) >>> >>> +bool ct_in_irq(void) >>> +{ >>> +    long nesting = ct_nmi_nesting(); >>> + >>> +    return (nesting && nesting != CT_NESTING_IRQ_NONIDLE); >>> +} >> >> Oh gosh, thanks for spotting that! Indeed, I had changed it to != 0 in the last >> version but applied an older patch. I will fix it in the tree. Thank you again! >> >> Neeraj, would you like this as a separate commit that you can then squash? Or >> could you fix it up in your tree? >> > Qi, Xiongfeng, I am currently working on alternative fix after discussing with > the crew. I will keep you posted with the fix, and would it to be good to get > your testing on it once I have it (hopefully in couple of days), thanks for the > report! Sure, we are glad to help test once we get the fix patch. Thanks, Xiongfeng > > - Joel > > . >