[PATCH 4.3 055/125] mac80211: fix divide by zero when NOA update

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.3 055/125] mac80211: fix divide by zero when NOA update
Date	2015-12-07 16:10 +0100
Message-ID	<qD5Am-6co-15@gated-at.bofh.it> (permalink)
References	<qD5Am-6co-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

4.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Janusz.Dziedzic@tieto.com" <Janusz.Dziedzic@tieto.com>

commit 519ee6918b91abdc4bc9720deae17599a109eb40 upstream.

In case of one shot NOA the interval can be 0, catch that
instead of potentially (depending on the driver) crashing
like this:

divide error: 0000 [#1] SMP
[...]
Call Trace:
<IRQ>
[<ffffffffc08e891c>] ieee80211_extend_absent_time+0x6c/0xb0 [mac80211]
[<ffffffffc08e8a17>] ieee80211_update_p2p_noa+0xb7/0xe0 [mac80211]
[<ffffffffc069cc30>] ath9k_p2p_ps_timer+0x170/0x190 [ath9k]
[<ffffffffc070adf8>] ath_gen_timer_isr+0xc8/0xf0 [ath9k_hw]
[<ffffffffc0691156>] ath9k_tasklet+0x296/0x2f0 [ath9k]
[<ffffffff8107ad65>] tasklet_action+0xe5/0xf0
[...]

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/util.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2951,6 +2951,13 @@ ieee80211_extend_noa_desc(struct ieee802
 	if (end > 0)
 		return false;
 
+	/* One shot NOA  */
+	if (data->count[i] == 1)
+		return false;
+
+	if (data->desc[i].interval == 0)
+		return false;
+
 	/* End time is in the past, check for repetitions */
 	skip = DIV_ROUND_UP(-end, data->desc[i].interval);
 	if (data->count[i] < 255) {


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

[PATCH 4.3 055/125] mac80211: fix divide by zero when NOA update Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-12-07 16:10 +0100

csiph-web