linux-kernel - Re: [PATCH RFC v2 0/6] staging: r8188eu: avoid uninit value bugs

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Date:   Sun, 22 Aug 2021 20:38:11 +0300
From:   Pavel Skripkin <paskripkin@...il.com>
To:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>,
        Larry.Finger@...inger.net, phil@...lpotter.co.uk,
        gregkh@...uxfoundation.org, straube.linux@...il.com
Cc:     linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC v2 0/6] staging: r8188eu: avoid uninit value bugs

On 8/22/21 8:36 PM, Fabio M. De Francesco wrote:
> On Sunday, August 22, 2021 4:35:05 PM CEST Pavel Skripkin wrote:
>> Hi, Greg, Larry and Phillip!
>> 
>> I noticed, that new staging driver was added like 3 weeks ago and I decided
>> to look at the code, because drivers in staging directory are always buggy.
>> 
>> The first thing I noticed is *no one* was checking read operations result, but
>> it can fail and driver may start writing random stack values into registers. It
>> can cause driver misbehavior or device misbehavior.
>> 
>> To avoid this type of bugs, I've changed rtw_read* API. Now all rtw_read
>> funtions return an error, when something went wrong with usb transfer.
>> 
>> It helps callers to break/return earlier and don't write random values to
>> registers or to rely on random values.
>> 
>> Why is this pacth series RFC?
>>   1. I don't have this device and I cannot test these changes.
>>   2. I don't know how to handle errors in each particular case. For now, function
>>      just returns or returns an error. That's all. I hope, driver maintainers will
>>      help with these bits.
>>   3. I guess, I handled not all uninit value bugs here. I hope, I fixed
>>      at least half of them
>> 
>> v1 -> v2:
>>   1. Make rtw_read*() return an error instead of initializing pointer to error
>>   2. Split one huge patch to smaller ones for each rtw_read{8,16,32} function
>>      changes
>>   3. Add new macro for printing register values (It helps to not copy-paste error
>>      handling)
>>   4. Removed {read,write}_macreg (Suggested by Phillip)
>>   5. Rebased on top of staging-next
>>   6. Cleaned checkpatch errors and warnings
>> 
>> Only build-tested, since I don't have device with r8118eu chip
>> 
>> Pavel Skripkin (6):
>>   staging: r8188eu: remove {read,write}_macreg
>>   staging: r8188eu: add helper macro for printing registers
>>   staging: r8188eu: add error handling of rtw_read8
>>   staging: r8188eu: add error handling of rtw_read16
>>   staging: r8188eu: add error handling of rtw_read32
>>   staging: r8188eu: make ReadEFuse return an int
> 
> Hi Pavel,
> 
> I've just read your v2 of the series. I had no time to read each and every line,
> however, I suppose that I saw enough to say that I think they are a huge
> improvement over v1. I really like your patches and if I were you, I'd drop
> that RFC tag.
> 

Thank you, Fabio! I appreciate it :)


With regards,
Pavel Skripkin