Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
Message-ID: <fd356230-c9b1-2824-d073-83975bd31be9@gmail.com>
Date:   Sun, 3 Apr 2022 15:19:57 +0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: staging: r8188eu: how to handle nested mutex under spinlock
Content-Language: en-US
From:   Pavel Skripkin <paskripkin@gmail.com>
To:     Michael Straube <straube.linux@gmail.com>,
        "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc:     Greg KH <gregkh@linuxfoundation.org>,
        Larry Finger <Larry.Finger@lwfinger.net>,
        Phillip Potter <phil@philpotter.co.uk>,
        "open list:STAGING SUBSYSTEM" <linux-staging@lists.linux.dev>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <356c24cf-625b-eea2-2c04-ce132d881cac@gmail.com>
 <1813843.tdWV9SEqCh@leap> <942bbcb6-725d-9b47-5dfe-f105d30ea6b7@gmail.com>
 <7365301.EvYhyI6sBW@leap> <bf1137fa-5051-a834-0c1f-042c5a8074a3@gmail.com>
 <3fb13fee-a605-7f2e-81ad-45148082a733@gmail.com>
In-Reply-To: <3fb13fee-a605-7f2e-81ad-45148082a733@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 4/3/22 14:48, Pavel Skripkin wrote:
> On 4/3/22 14:41, Michael Straube wrote:
>> 
>> Hi Fabio,
>> 
>> wait..
>> 
>> rtw_set_802_11_disassociate() calls rtw_pwr_wakeup() only if
>> check_fwstate(pmlmepriv, _FW_LINKED) is true.
>> 
>> 
>> 	if (check_fwstate(pmlmepriv, _FW_LINKED)) {
>> 		rtw_disassoc_cmd(padapter, 0, true);
>> 		rtw_indicate_disconnect(padapter);
>> 		rtw_free_assoc_resources(padapter, 1);
>> 		rtw_pwr_wakeup(padapter);
>> 	}
>> 
> 
> msleep() cannot be called in atomic context:
> 
> drivers/staging/r8188eu/core/rtw_pwrctrl.c:379
> 
>    	if (pwrpriv->ps_processing) {
>    		while (pwrpriv->ps_processing && rtw_get_passing_time_ms(start) <= 3000)
>    			msleep(10);
>    	}
> 

Hm, just wondering, shouldn't we annotate load from 
pwrpriv->ps_processing with READ_ONCE() inside while loop?

IIUC compiler might want to cache first load into register and we will 
stuck here forever.


Am I missing something?


With regards,
Pavel Skripkin