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minstrel: fix warning if lowest supported rate index is not 0

PATCH In review Christian Lamparter 2 participants 2 messages Dec 22, 2008 mac80211

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Christian Lamparter

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#0 lore raw

PATCH 1/1 minstrel: fix warning if lowest supported rate index is not 0

This patch fixes the following WARNING (caused by rix_to_ndx): "

Quoted 10 lines
WARNING: at net/mac80211/rc80211_minstrel.c:69 minstrel_rate_init+0xd2/0x33a [mac80211]()
[...]
Call Trace:
warn_on_slowpath+0x51/0x75
_format_mac_addr+0x4c/0x88
minstrel_rate_init+0xd2/0x33a [mac80211]
print_mac+0x16/0x1b
schedule_hrtimeout_range+0xdc/0x107
ieee80211_add_station+0x158/0x1bd [mac80211]
nl80211_new_station+0x1b3/0x20b [cfg80211]

The reason is that I'm experimenting with "g" only mode on a 802.11 b/g card.

Therefore rate_lowest_index returns 4 (= 6Mbit, instead of usual 0 = 1Mbit). Since mi->r array is initialized with zeros in minstrel_alloc_sta, rix_to_ndx has a hard time to find the 6Mbit entry and will trigged the WARNING.

Signed-off-by Christian Lamparter <[email protected]>

---
nbd?

Is this the correct? or should we initialize mi->r array in minstrel_alloc_sta?
---
Johannes,

yeah, this fixes the problems I described in
"[PATCH] ath9k: Fix a NULL pointer dereference in ath_rate_get". sorry for the noise!
---

net/mac80211/rc80211_minstrel.c +6 -4
index 2b3b490..3824990 100644
@@ -395,13 +395,15 @@ minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
 {
 	struct minstrel_sta_info *mi = priv_sta;
 	struct minstrel_priv *mp = priv;
-	struct minstrel_rate *mr_ctl;
+	struct ieee80211_local *local = hw_to_local(mp->hw);
+	struct ieee80211_rate *ctl_rate;
 	unsigned int i, n = 0;
 	unsigned int t_slot = 9; /* FIXME: get real slot time */
 
 	mi->lowest_rix = rate_lowest_index(sband, sta);
-	mr_ctl = &mi->r[rix_to_ndx(mi, mi->lowest_rix)];
-	mi->sp_ack_dur = mr_ctl->ack_time;
+	ctl_rate = &sband->bitrates[mi->lowest_rix];
+	mi->sp_ack_dur = ieee80211_frame_duration(local, 10, ctl_rate->bitrate,
+				!!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1);
 
 	for (i = 0; i < sband->n_bitrates; i++) {
 		struct minstrel_rate *mr = &mi->r[n];

@@ -416,7 +418,7 @@ minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
 
 		mr->rix = i;
 		mr->bitrate = sband->bitrates[i].bitrate / 5;
-		calc_rate_durations(mi, hw_to_local(mp->hw), mr,
+		calc_rate_durations(mi, local, mr,
 				&sband->bitrates[i]);
 
 		/* calculate maximum number of retransmissions before
Acked-by on v1 1/1
#1 lore raw
Quoted 12 lines · Christian Lamparter

This patch fixes the following WARNING (caused by rix_to_ndx): "

Quoted 10 lines
WARNING: at net/mac80211/rc80211_minstrel.c:69 minstrel_rate_init+0xd2/0x33a [mac80211]()
[...]
Call Trace:
warn_on_slowpath+0x51/0x75
_format_mac_addr+0x4c/0x88
minstrel_rate_init+0xd2/0x33a [mac80211]
print_mac+0x16/0x1b
schedule_hrtimeout_range+0xdc/0x107
ieee80211_add_station+0x158/0x1bd [mac80211]
nl80211_new_station+0x1b3/0x20b [cfg80211]
Quoted 7 lines

The reason is that I'm experimenting with "g" only mode on a 802.11 b/g card.

Therefore rate_lowest_index returns 4 (= 6Mbit, instead of usual 0 = 1Mbit). Since mi->r array is initialized with zeros in minstrel_alloc_sta, rix_to_ndx has a hard time to find the 6Mbit entry and will trigged the WARNING.

Signed-off-by Christian Lamparter <[email protected]>
Acked-by Felix Fietkau <[email protected]>