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From: Linus Walleij <linus.walleij@linaro.org>
Date: Sat, 27 Jan 2024 17:37:25 +0100
Message-ID: <CACRpkdbpQNoh_ESB=CcUcP0_pcvDYCs9FeJ_wY74a7WJ77sLBg@mail.gmail.com>
Subject: Re: [PATCH] wifi: brcmfmac: Adjust n_channels usage for __counted_by
To: Kees Cook <keescook@chromium.org>
Cc: Arend van Spriel <aspriel@gmail.com>, Franky Lin <franky.lin@broadcom.com>, 
	Hante Meuleman <hante.meuleman@broadcom.com>, Kalle Valo <kvalo@kernel.org>, 
	Chi-hsien Lin <chi-hsien.lin@infineon.com>, Ian Lin <ian.lin@infineon.com>, 
	Johannes Berg <johannes.berg@intel.com>, Wright Feng <wright.feng@cypress.com>, 
	Hector Martin <marcan@marcan.st>, linux-wireless@vger.kernel.org, 
	brcm80211-dev-list.pdl@broadcom.com, 
	"Gustavo A. R. Silva" <gustavoars@kernel.org>, Jisoo Jang <jisoo.jang@yonsei.ac.kr>, 
	Hans de Goede <hdegoede@redhat.com>, Aloka Dixit <quic_alokad@quicinc.com>, 
	John Keeping <john@keeping.me.uk>, Jeff Johnson <quic_jjohnson@quicinc.com>, 
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
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On Fri, Jan 26, 2024 at 11:31=E2=80=AFPM Kees Cook <keescook@chromium.org> =
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:

Makes perfect sense.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij