On Mon, 2012-03-12 at 01:20 +0100, Willy Tarreau wrote: > 2.6.32-longterm review patch. If anyone has any objections, please let me > know. > > ------------------ > > From: Mohammed Shafi Shajakhan <[email protected]> > > commit 8617b093d0031837a7be9b32bc674580cfb5f6b5 upstream. > > rate control algorithms concludes the rate as invalid > with rate[i].idx < -1 , while they do also check for rate[i].count is > non-zero. it would be safer to zero initialize the 'count' field. > recently we had a ath9k rate control crash where the ath9k rate control > in ath_tx_status assumed to check only for rate[i].count being non-zero > in one instance and ended up in using invalid rate index for > 'connection monitoring NULL func frames' which eventually lead to the crash. > thanks to Pavel Roskin for fixing it and finding the root cause. > https://bugzilla.redhat.com/show_bug.cgi?id=768639
In 2.6.32, ath_tx_status() checks that rates[i].idx >= 0, so it properly ignores these dummy entries. Further, there is code further down the rate_control_get_rate() function that sets .idx only and appears to depend on the initialisation of .count = 1. So I'm pretty sure this patch is wrong for 2.6.32; it could be backported but I don't think the change is necessary anyway. Ben. > Cc: [email protected] > Cc: Pavel Roskin <[email protected]> > Signed-off-by: Mohammed Shafi Shajakhan <[email protected]> > Signed-off-by: John W. Linville <[email protected]> > > diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c > index ad64f4d..f9b8e81 100644 > --- a/net/mac80211/rate.c > +++ b/net/mac80211/rate.c > @@ -344,7 +344,7 @@ void rate_control_get_rate(struct ieee80211_sub_if_data > *sdata, > for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) { > info->control.rates[i].idx = -1; > info->control.rates[i].flags = 0; > - info->control.rates[i].count = 1; > + info->control.rates[i].count = 0; > } > > if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) > > > -- > To unsubscribe from this list: send the line "unsubscribe stable" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Ben Hutchings Life would be so much easier if we could look at the source code.
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