From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gustavo A. R. Silva" Subject: Re: [PATCH] ath10k: htt_rx: Fix signedness bug in ath10k_update_per_peer_tx_stats Date: Fri, 5 Oct 2018 21:14:27 +0200 Message-ID: References: <20181005184245.GA11700@embeddedor.com> <3a55bec6-d20d-f500-e741-b228a86b7117@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Ben Greear , Kalle Valo , "David S. Miller" Return-path: In-Reply-To: <3a55bec6-d20d-f500-e741-b228a86b7117@candelatech.com> Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 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 >> --- >>  drivers/net/wireless/ath/ath10k/htt_rx.c | 3 ++- >>  1 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, >>                  struct ath10k_per_peer_tx_stats *peer_stats) >>  { >>      struct ath10k_sta *arsta = (struct ath10k_sta *)sta->drv_priv; >> -    u8 rate = 0, rate_idx = 0, sgi; >> +    u8 rate = 0, sgi; >> +    s8 rate_idx = 0; >>      struct rate_info txrate; >> >>      lockdep_assert_held(&ar->data_lock); >> > >