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

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Date:   Sun, 22 Aug 2021 19:36:13 +0200
From:   "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To:     Larry.Finger@...inger.net, phil@...lpotter.co.uk,
        gregkh@...uxfoundation.org, straube.linux@...il.com,
        Pavel Skripkin <paskripkin@...il.com>
Cc:     linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Pavel Skripkin <paskripkin@...il.com>
Subject: Re: [PATCH RFC v2 0/6] staging: r8188eu: avoid uninit value bugs

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.

Thanks,

Fabio
v1 design.
not needed because