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 2CB09242D89; Tue, 22 Jul 2025 11:06:22 +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=1753182386; cv=none; b=SQTP6p6BjicawP96JzYXKj4w9qmTzSXlwSx15C2fMr1XXcFZK1lv0kypfUdNtXA0RcUKoeskhG//1kSzaR/dOElrd+2Cv0Lm+9g1FTmifmqQXmlSzyEyqRtQI9vY47rxCmfqy+o1x2Pkeh8O9pKQkqiZMQnRZIcRFHSIL0AYoTE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753182386; c=relaxed/simple; bh=gYJWcfMA+4JwuKa4pqmCzXGEn9gI6ZQKiZEdFTNaSKY=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=GabaNLjl95Nhy4S/aArTG+jvrf2CSffQEo2WZ4nFhATi/4Kld2FnTZ/2MOewOoCjGRxvvuO50sy5pfhsZ9hps6E4vScbotOwVB+17QN7I/80Rom+hcDVUbN1SGlKeJkFml15bZyG030qnS5JMquSnfhyHY+SN/rGQIk/dErbjGA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=h-partners.com; arc=none smtp.client-ip=45.249.212.190 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=h-partners.com Received: from mail.maildlp.com (unknown [172.19.162.112]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4bmZB14bmqz2RVwG; Tue, 22 Jul 2025 19:03:05 +0800 (CST) Received: from dggemv712-chm.china.huawei.com (unknown [10.1.198.32]) by mail.maildlp.com (Postfix) with ESMTPS id BDDAB1402C1; Tue, 22 Jul 2025 19:05:17 +0800 (CST) Received: from kwepemn100009.china.huawei.com (7.202.194.112) by dggemv712-chm.china.huawei.com (10.1.198.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 22 Jul 2025 19:05:17 +0800 Received: from [10.67.121.59] (10.67.121.59) by kwepemn100009.china.huawei.com (7.202.194.112) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 22 Jul 2025 19:05:16 +0800 Message-ID: Date: Tue, 22 Jul 2025 19:05:16 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ACPI: processor: idle: Fix resource rollback in acpi_processor_power_init To: "Rafael J. Wysocki" CC: , , , , , , , , , References: <20250619061327.1674384-1-lihuisong@huawei.com> <6a35291a-32e8-461e-a0e5-405b7b5d24ce@huawei.com> <4c1926ef-f9fa-49d5-8d5f-ed4ee2638d62@huawei.com> From: "lihuisong (C)" In-Reply-To: <4c1926ef-f9fa-49d5-8d5f-ed4ee2638d62@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems100001.china.huawei.com (7.221.188.238) To kwepemn100009.china.huawei.com (7.202.194.112) Hi Rafael, Can you take a look at my reply? If it is ok to you, I will send it later. /Huisong 在 2025/7/14 9:33, lihuisong (C) 写道: > > 在 2025/7/3 19:09, Rafael J. Wysocki 写道: >> On Thu, Jul 3, 2025 at 8:23 AM lihuisong (C) >> wrote: >>> Hi, >>> >>> Thanks for your review. >>> >>> >>> 在 2025/7/3 1:42, Rafael J. Wysocki 写道: >>>> On Thu, Jun 19, 2025 at 8:13 AM Huisong Li >>>> wrote: >>>>> There are two resource rollback issues in acpi_processor_power_init: >>>>> 1> Do not unregister acpi_idle_driver when do kzalloc failed. >>>>> 2> Do not free cpuidle device memory when register cpuidle device >>>>> failed. >>>>> >>>>> Signed-off-by: Huisong Li >>>>> --- >>>>>    drivers/acpi/processor_idle.c | 24 +++++++++++++++++------- >>>>>    1 file changed, 17 insertions(+), 7 deletions(-) >>>>> >>>>> diff --git a/drivers/acpi/processor_idle.c >>>>> b/drivers/acpi/processor_idle.c >>>>> index 2c2dc559e0f8..3548ab9dac9e 100644 >>>>> --- a/drivers/acpi/processor_idle.c >>>>> +++ b/drivers/acpi/processor_idle.c >>>>> @@ -1392,8 +1392,10 @@ int acpi_processor_power_init(struct >>>>> acpi_processor *pr) >>>>>                   } >>>>> >>>>>                   dev = kzalloc(sizeof(*dev), GFP_KERNEL); >>>>> -               if (!dev) >>>>> -                       return -ENOMEM; >>>>> +               if (!dev) { >>>>> +                       retval = -ENOMEM; >>>>> +                       goto unregister_driver; >>>> No, unregistering the driver here is pointless. >>> I don't quite understand why here is pointless. Can you explain it? >> When this function is run for another CPU, it will attempt to register >> the driver again if it is unregistered here. > Yeah, got it. > So registering cpuidle also has a potential race issue here. >> >> Quite frankly, the driver should be registered before running this >> function because it is a CPU hotplug callback and registering a >> cpuidle driver from within it is quite questionable. >> >> Alternatively, it can be registered when all of the CPUs have been >> brought up. > Agree with you. > The reason why is that the initialization of acpi_idle_driver depands > on the power management information of CPU. > But the power management information of CPU is obtained in this callback. > I have an idea. > Because acpi_idle_driver is applied to all possiable CPUs. And use the > power information of the first onlined CPU to initialize and register > acpi_idle_driver, currently. > So I think we can use this logic and dependency to extract a function > to initialize and register acpi_idle_driver. And put this function to > acpi_processor_driver_init(). > I tested it is ok. > What do you think about this? > > /Huisong >> >>>>> +               } >>>>>                   per_cpu(acpi_cpuidle_device, pr->id) = dev; >>>>> >>>>>                   acpi_processor_setup_cpuidle_dev(pr, dev); >>>>> @@ -1402,14 +1404,22 @@ int acpi_processor_power_init(struct >>>>> acpi_processor *pr) >>>>>                    * must already be registered before registering >>>>> device >>>>>                    */ >>>>>                   retval = cpuidle_register_device(dev); >>>>> -               if (retval) { >>>>> -                       if (acpi_processor_registered == 0) >>>>> - cpuidle_unregister_driver(&acpi_idle_driver); >>>> Pretty much the same as here. >>>> >>>> It would be good to clean up dev here though. >>> It is ok if above is pointless. >>>>> -                       return retval; >>>>> -               } >>>>> +               if (retval) >>>>> +                       goto free_cpuidle_device; >>>>> + >>>>>                   acpi_processor_registered++; >>>>>           } >>>>>           return 0; >>>>> + >>>>> +free_cpuidle_device: >>>>> +       per_cpu(acpi_cpuidle_device, pr->id) = NULL; >>>>> +       kfree(dev); >>>>> + >>>>> +unregister_driver: >>>>> +       if (acpi_processor_registered == 0) >>>>> + cpuidle_unregister_driver(&acpi_idle_driver); >>>>> + >>>>> +       return retval; >>>>>    } >>>>> >>>>>    int acpi_processor_power_exit(struct acpi_processor *pr) >>>>> -- >>>>> 2.33.0 >>>>>