Re: [PATCH] wifi: brcmfmac: Adjust n_channels usage for __counted_by

[Arend Van Spriel]

On 2/2/2024 11:34 AM, Kalle Valo wrote:
> Arend Van Spriel <aspriel@xxxxxxxxx> writes:
>
> > On 2/2/2024 10:58 AM, Arend Van Spriel wrote:
> >
> > > On 2/1/2024 11:04 AM, Kalle Valo wrote:
> > > > Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > > >
> > > > > After commit e3eac9f32ec0 ("wifi: cfg80211: Annotate struct
> > > > > cfg80211_scan_request with __counted_by"), the compiler may enforce
> > > > > dynamic array indexing of req->channels to stay below n_channels. As a
> > > > > result, n_channels needs to be increased _before_ accessing the newly
> > > > > added array index. Increment it first, then use "i" for the prior index.
> > > > > Solves this warning in the coming GCC that has __counted_by support:
> > > > >
> > > > > ../drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c: In
> > > > > function 'brcmf_internal_escan_add_info':
> > > > > ../drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:3783:46: warning: operation on 'req->
> > > > > n_channels' may be undefined [-Wsequence-point]
> > > > >    3783 |                 req->channels[req->n_channels++] = chan;
> > > > >         |                               ~~~~~~~~~~~~~~~^~
> > > > >
> > > > > Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct
> > > > > cfg80211_scan_request with __counted_by")
> > > > > Cc: Arend van Spriel <aspriel@xxxxxxxxx>
> > > > > Cc: Franky Lin <franky.lin@xxxxxxxxxxxx>
> > > > > Cc: Hante Meuleman <hante.meuleman@xxxxxxxxxxxx>
> > > > > Cc: Kalle Valo <kvalo@xxxxxxxxxx>
> > > > > Cc: Chi-hsien Lin <chi-hsien.lin@xxxxxxxxxxxx>
> > > > > Cc: Ian Lin <ian.lin@xxxxxxxxxxxx>
> > > > > Cc: Johannes Berg <johannes.berg@xxxxxxxxx>
> > > > > Cc: Wright Feng <wright.feng@xxxxxxxxxxx>
> > > > > Cc: Hector Martin <marcan@xxxxxxxxx>
> > > > > Cc: linux-wireless@xxxxxxxxxxxxxxx
> > > > > Cc: brcm80211-dev-list.pdl@xxxxxxxxxxxx
> > > > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> > > > > Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> > > > > Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > > > > Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> > > >
> > > > I'm planning to queue this for wireless tree. Arend, ack?
> > > This slipped past my broadcom email. As the Fixes commit is in 6.7 I
> > > would say ACK.
>
> Thanks.
>
> > Cc: to stable?
>
> Is commit e3eac9f32ec0 in stable releases? (I don't follow stable and
> don't know what commits they take.) I propose that as we have Fixes tag
> let's not add cc but instead let stable maintainers to decide.

I confirmed the commit was in 6.7 and the latest released kernel is 
always handled by stable kernel team. kernel.org main page always shows 
the active stable/longterm releases. That said I have no problem with 
your proposal.

Gr. AvS