Message-ID: <541FF25B.9000404@broadcom.com> (sfid-20140922_115710_154759_585C076D)
Date: Mon, 22 Sep 2014 11:56:43 +0200
From: Arend van Spriel <arend@broadcom.com>
MIME-Version: 1.0
To: Emil Goode <emilgoode@gmail.com>
CC: Brett Rudley <brudley@broadcom.com>,
	"Franky (Zhenhui) Lin" <frankyl@broadcom.com>,
	Hante Meuleman <meuleman@broadcom.com>,
	"John W. Linville" <linville@tuxdriver.com>,
	Pieter-Paul Giesberts <pieterpg@broadcom.com>,
	Daniel Kim <dekim@broadcom.com>,
	<linux-wireless@vger.kernel.org>,
	<brcm80211-dev-list@broadcom.com>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <kernel-janitors@vger.kernel.org>
Subject: Re: [PATCH] brcmfmac: Fix off by one bug in brcmf_count_20mhz_channels()
References: <1411253932-27973-1-git-send-email-emilgoode@gmail.com>
In-Reply-To: <1411253932-27973-1-git-send-email-emilgoode@gmail.com>
Content-Type: text/plain; charset="ISO-8859-1"; format=flowed
Sender: linux-wireless-owner@vger.kernel.org

On 09/21/14 00:58, Emil Goode wrote:
> In the brcmf_count_20mhz_channels function we are looping through a list
> of channels received from firmware. Since the index of the first channel
> is 0 the condition leads to an off by one bug. This is causing us to hit
> the WARN_ON_ONCE(1) calls in the brcmu_d11n_decchspec function, which is
> how I discovered the bug.

The fix is fine. Would like to know what exactly is going wrong. Can you 
provide a kernel log with brcmfmac debugging enabled, ie. insmod 
brcmfmac.ko debug=0x1416

Regards,
Arend

> Introduced by:
> commit b48d891676f756d48b4d0ee131e4a7a5d43ca417
> ("brcmfmac: rework wiphy structure setup")
>
> Signed-off-by: Emil Goode<emilgoode@gmail.com>
> ---
>   drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c b/drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c
> index 02fe706..93b5dd9 100644
> --- a/drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c
> +++ b/drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c
> @@ -4918,7 +4918,7 @@ static void brcmf_count_20mhz_channels(struct brcmf_cfg80211_info *cfg,
>   	struct brcmu_chan ch;
>   	int i;
>
> -	for (i = 0; i<= total; i++) {
> +	for (i = 0; i<  total; i++) {
>   		ch.chspec = (u16)le32_to_cpu(chlist->element[i]);
>   		cfg->d11inf.decchspec(&ch);
>