Re: [PATCH] ath10k: htt_rx: Fix signedness bug in ath10k_update_per_peer_tx_stats

[Anilkumar Kolli]

On 2018-10-06 00:45, Gustavo A. R. Silva wrote:
> On 10/5/18 9:14 PM, Gustavo A. R. Silva wrote:
> > On 10/5/18 9:09 PM, Ben Greear wrote:
> > > On 10/05/2018 11:42 AM, Gustavo A. R. Silva wrote:
> > > > Currently, the error handling for the call to function
> > > > ath10k_get_legacy_rate_idx() doesn't work because
> > > > *rate_idx* is of type u8 (8 bits, unsigned), which
> > > > makes it impossible for it to hold a value less
> > > > than 0.
> > > >
> > > > Fix this by changing the type of variable *rate_idx*
> > > > to s8 (8 bits, signed).
> > >
> > > There are more than 127 rates, are you sure this is doing
> > > what you want?
> >
> > Based on the following function, rate_idx can only hold values from 0 
> > to 11
>
> ... and of course -EINVAL too
>
> > static inline int ath10k_get_legacy_rate_idx(struct ath10k *ar, u8 
> > rate)
> > {
> >         static const u8 legacy_rates[] = {1, 2, 5, 11, 6, 9, 12,
> >                                           18, 24, 36, 48, 54};
> >         int i;
> >
> >         for (i = 0; i < ARRAY_SIZE(legacy_rates); i++) {
> >                 if (rate == legacy_rates[i])
> >                         return i;
> >         }
> >
> >         ath10k_warn(ar, "Invalid legacy rate %hhd peer stats", rate);
> >         return -EINVAL;
> > }
> >
> > Thanks
> > --
> > Gustavo
> >
> > > Thanks,
> > > Ben
> > >
> > > > Addresses-Coverity-ID: 1473914 ("Unsigned compared against 0")
> > > > Fixes: 0189dbd71cbd ("ath10k: get the legacy rate index to update 
> > > > the txrate table")
> > > > Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> > > > ---
> > > > Âdrivers/net/wireless/ath/ath10k/htt_rx.c | 3 ++-
> > > > Â1 file changed, 2 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/net/wireless/ath/ath10k/htt_rx.c 
> > > > b/drivers/net/wireless/ath/ath10k/htt_rx.c
> > > > index f240525..edd0e74 100644
> > > > --- a/drivers/net/wireless/ath/ath10k/htt_rx.c
> > > > +++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
> > > > @@ -2753,7 +2753,8 @@ ath10k_update_per_peer_tx_stats(struct ath10k 
> > > > *ar,
> > > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct ath10k_per_peer_tx_stats *peer_stats)
> > > > Â{
> > > > ÂÂÂÂ struct ath10k_sta *arsta = (struct ath10k_sta *)sta->drv_priv;
> > > > -ÂÂÂ u8 rate = 0, rate_idx = 0, sgi;
> > > > +ÂÂÂ u8 rate = 0, sgi;
> > > > +ÂÂÂ s8 rate_idx = 0;
> > > > ÂÂÂÂ struct rate_info txrate;
> > > >
> > > > ÂÂÂÂ lockdep_assert_held(&ar->data_lock);

I have sent a patch to address this,
https://patchwork.kernel.org/patch/10611943/

Thanks
Anil.