From 519ee6918b91abdc4bc9720deae17599a109eb40 Mon Sep 17 00:00:00 2001 From: "Janusz.Dziedzic@tieto.com" Date: Tue, 27 Oct 2015 08:35:11 +0100 Subject: [PATCH] mac80211: fix divide by zero when NOA update 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: [] ieee80211_extend_absent_time+0x6c/0xb0 [mac80211] [] ieee80211_update_p2p_noa+0xb7/0xe0 [mac80211] [] ath9k_p2p_ps_timer+0x170/0x190 [ath9k] [] ath_gen_timer_isr+0xc8/0xf0 [ath9k_hw] [] ath9k_tasklet+0x296/0x2f0 [ath9k] [] tasklet_action+0xe5/0xf0 [...] Cc: stable@vger.kernel.org [3.16+, due to d463af4a1c34 using it] Signed-off-by: Janusz Dziedzic Signed-off-by: Johannes Berg --- net/mac80211/util.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/mac80211/util.c b/net/mac80211/util.c index 8274c86296f9..c5ed42f2f667 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -2958,6 +2958,13 @@ ieee80211_extend_noa_desc(struct ieee80211_noa_data *data, u32 tsf, int i) 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) {