Re: [PATCH] brcmfmac: Fix off by one bug in brcmf_count_20mhz_channels()

[Arend van Spriel]

On 09/23/14 01:08, Emil Goode wrote:
> Hello Arend,
>
> Sorry for the late reply. I have attached a kernel log with brcmfmac
> debugging enabled (without my patch applied).
>
> Let me know if I can provide any other useful information.

No problem, Emil

I was wondering what was returned on "chanspecs" query. So 17 channel 
configs which is expected.

Regards,
Arend

> Best regards,
>
> Emil
>
> On Mon, Sep 22, 2014 at 11:56:43AM +0200, Arend van Spriel wrote:
> > 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@xxxxxxxxx>
> > > ---
> > >   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);

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