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

Pavel Skripkin
2021-08-22T20:19:29Z

On 8/22/21 11:06 PM, Fabio M. De Francesco wrote:
> On Sunday, August 22, 2021 7:38:11 PM CEST Pavel Skripkin wrote:
>> 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
>
> Hi Pavel,
>
> I've read more code of your series and I'm ready to give a formal ack. However,
> I'm not sure about the rules: can it be also given to RFC or only to "real" patches?
>
> As I've already said, they look good and I like them. So, the entire series is...
>

AFAIK, RFC patches can be treated as normal patches, if
reviewers/maintainers don't have objections to code. I am not sure about
it, since it's my first experience with RFCs :)

Anyway, thank you for ACKing. Let's see what Larry thinks about it. I
believe, he can find some bugs in my code since it's not tested at all
:) I hope, my r8118eu device will come soon and I will be able to test
this series...

> Acked-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
>
> If the rules don't allow to formally ack RFC, I will be happy to ack again the final product.
>
> I also want to say that I enjoyed discussing this work with you on this long thread. :-)
>

Me too, thank you. Technical discussions are the best part of linux
kernel development process, IMO :)

With regards,
Pavel Skripkin