[PATCH][next] mac80211: minstrel_ht: fix infinite loop because supported is not being shifted

[PATCH][next] mac80211: minstrel_ht: fix infinite loop because supported is not being shifted

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

Currently the for-loop will spin forever if variable supported is
non-zero because supported is never changed.  Fix this by adding in
the missing right shift of supported.

Addresses-Coverity: ("Infinite loop")
Fixes: 48cb39522a9d ("mac80211: minstrel_ht: improve rate probing for devices with static fallback")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 net/mac80211/rc80211_minstrel_ht.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index a01168514840..0ef2633349b5 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -634,7 +634,7 @@ minstrel_ht_rate_sample_switch(struct minstrel_priv *mp,
 		u16 supported = mi->supported[g_idx];
 
 		supported >>= mi->max_tp_rate[0] % MCS_GROUP_RATES;
-		for (i = 0; supported; i++) {
+		for (i = 0; supported; supported >>= 1, i++) {
 			if (!(supported & 1))
 				continue;
 
-- 
2.20.1

Re: [PATCH][next] mac80211: minstrel_ht: fix infinite loop because supported is not being shifted

[Felix Fietkau]

On 2019-08-22 14:20, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the for-loop will spin forever if variable supported is
> non-zero because supported is never changed.  Fix this by adding in
> the missing right shift of supported.
> 
> Addresses-Coverity: ("Infinite loop")
> Fixes: 48cb39522a9d ("mac80211: minstrel_ht: improve rate probing for devices with static fallback")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Felix Fietkau <nbd@nbd.name>

Thanks,

- Felix