get_expected_throughput introduces a kernel oops on sta_set_sinfo calls

["Jean-Pierre Tosoni" <jp.tosoni@acksys.fr>]

Hi list,

I am using compat-wireless-20132-04-16 with kernel 3.3.8.
I experienced a kernel oops after applying the "get_expected_throughput"
patches series from Antonio Quartulli.
It happens when a station_dump is issued from userspace while an association
has begun but does not complete immediately due to bad channel.
After some debugging I made this patch which solves the issue:
===========================================================================
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@@ -708,6 +708,15 @@ static u32 minstrel_get_expected_throughput(
 	struct minstrel_sta_info *mi = priv_sta;
 	int idx = mi->max_tp_rate[0];
 
+	if (!mi->r) {
+		/*
+		 * Happens if get_expected_throughput() is called by
+		 * ieee80211_dump_station during association from HT
+		 * client to AP, before getting the HT IE from the AP
+		 */
+		printk(KERN_ERR "minstrel: uninitialized station rates");
+		return 0; /* value suggested by J. Berg 25-apr-2014 */
+	}
 	/* convert pkt per sec in kbps (1200 is the average pkt size used
for
 	 * computing cur_tp
 	 */
===========================================================================

With this patch I get this trace (the timeout is expected, since the SNR is
very low):

[  359.798796] wlan0: authenticate with 92:a4:de:21:4f:85

[  359.813180] wlan0: direct probe to 92:a4:de:21:4f:85 (try 1/3)

[  359.922306] wlan0: direct probe to 92:a4:de:21:4f:85 (try 2/3)

[  360.005424] minstrel: uninitialized station rates

[  360.030318] wlan0: direct probe to 92:a4:de:21:4f:85 (try 3/3)

[  360.138294] wlan0: authentication with 92:a4:de:21:4f:85 timed out

Maybe station_dump should not dump the stations just created by an
yet-unanswered authentication request?
Or is my patch the right thing to do?

Regards
Jean-Pierre Tosoni