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Subject: Re: [BUG] mfd: ezx-pcap: Possible sleep-in-atomic-context bugs in
 pcap_adc_irq()
To:     Lee Jones <lee.jones@linaro.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <f83a444a-1943-6c8c-5cd4-88e2acb17fa6@gmail.com>
 <20180917010340.GA3900@dell>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <e371a365-7dac-8e20-4823-f5395602211d@gmail.com>
Date:   Mon, 17 Sep 2018 10:46:17 +0800
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On 2018/9/17 9:03, Lee Jones wrote:
> On Sat, 15 Sep 2018, Jia-Ju Bai wrote:
>
>> The driver may sleep in an interrupt handler.
>> The function call paths (from bottom to top) in Linux-4.17 are:
>>
>> [FUNC] mutex_lock_nested
>> drivers/mfd/ezx-pcap.c, 272:
>>      mutex_lock_nested in pcap_adc_irq (interrupt handler)
>>
>> [FUNC] mutex_lock_nested
>> drivers/mfd/ezx-pcap.c, 100:
>>      mutex_lock_nested in ezx_pcap_read
>> drivers/mfd/ezx-pcap.c, 281:
>>      ezx_pcap_read in pcap_adc_irq (interrupt handler)
>>
>> [FUNC] mutex_lock_nested
>> drivers/mfd/ezx-pcap.c, 85:
>>      mutex_lock_nested in ezx_pcap_write
>> drivers/mfd/ezx-pcap.c, 285:
>>      ezx_pcap_write in pcap_adc_irq (interrupt handler)
>>
>> [FUNC] mutex_lock_nested
>> drivers/mfd/ezx-pcap.c, 244:
>>      mutex_lock_nested in pcap_adc_trigger
>> drivers/mfd/ezx-pcap.c, 299:
>>      pcap_adc_trigger in pcap_adc_irq (interrupt handler)
>>
>> These bugs are found by my static analysis tool DSAC.
> Not sure what you want me to do with this.
>
> Do you have something in mind?
>

I find some possible bugs in this driver, but I do not know how to 
correctly fix them...
Could you find a good solution?


Best wishes,
Jia-Ju Bai