[PATCH] mac80211_hwsim: calculate if_combination.max_interfaces

* [PATCH] mac80211_hwsim: calculate if_combination.max_interfaces
@ 2019-03-23 12:43 Johannes Berg
  2019-03-28 15:36 ` [mac80211_hwsim] 5cf94a0ee7: WARNING:at_net/wireless/core.c:#wiphy_register[cfg80211] kernel test robot
  0 siblings, 1 reply; 2+ messages in thread
From: Johannes Berg @ 2019-03-23 12:43 UTC (permalink / raw)
  To: linux-wireless; +Cc: Johannes Berg

From: Johannes Berg <johannes.berg@intel.com>

If we just set this to 2048, and have multiple limits you
can select from, the total number might run over and cause
a warning in cfg80211. This doesn't make sense, so we just
calculate the total max_interfaces now.

Reported-by: syzbot+8f91bd563bbff230d0ee@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/mac80211_hwsim.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 77bce2d27841..1fe94dfee5c6 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -2644,7 +2644,7 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
 	enum nl80211_band band;
 	const struct ieee80211_ops *ops = &mac80211_hwsim_ops;
 	struct net *net;
-	int idx;
+	int idx, i;
 	int n_limits = 0;
 
 	if (WARN_ON(param->channels > 1 && !param->use_chanctx))
@@ -2768,8 +2768,12 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
 		goto failed_hw;
 	}
 
+	data->if_combination.max_interfaces = 0;
+	for (i = 0; i < n_limits; i++)
+		data->if_combination.max_interfaces +=
+			data->if_limits[n_limits].max;
+
 	data->if_combination.n_limits = n_limits;
-	data->if_combination.max_interfaces = 2048;
 	data->if_combination.limits = data->if_limits;
 
 	hw->wiphy->iface_combinations = &data->if_combination;
-- 
2.17.2


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