From 03695549aa76e877d596df188c266f06257b6a23 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Thu, 1 Mar 2018 14:30:09 +0300 Subject: [PATCH] mac80211_hwsim: Make hwsim_netgroup IDA hwsim_netgroup counter is declarated as int, and it is incremented every time a new net is created. After sizeof(int) net are created, it will overflow, and different net namespaces will have the same identifier. This patch fixes the problem by introducing IDA instead of int counter. IDA guarantees, all the net namespaces have the uniq identifier. Note, that after we do ida_simple_remove() in hwsim_exit_net(), and we destroy the ID, later there may be executed destroy_radio() from the workqueue. But destroy_radio() does not use the ID, so it's OK. Out of bounds of this patch, just as a report to wireless subsystem maintainer, destroy_radio() increaments hwsim_radios_generation without hwsim_radio_lock, so this may need one more patch to fix. Signed-off-by: Kirill Tkhai Signed-off-by: Johannes Berg --- drivers/net/wireless/mac80211_hwsim.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index 3c64afa..45ba846 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -253,7 +253,7 @@ static inline void hwsim_clear_chanctx_magic(struct ieee80211_chanctx_conf *c) static unsigned int hwsim_net_id; -static int hwsim_netgroup; +static struct ida hwsim_netgroup_ida = IDA_INIT; struct hwsim_net { int netgroup; @@ -267,11 +267,13 @@ static inline int hwsim_net_get_netgroup(struct net *net) return hwsim_net->netgroup; } -static inline void hwsim_net_set_netgroup(struct net *net) +static inline int hwsim_net_set_netgroup(struct net *net) { struct hwsim_net *hwsim_net = net_generic(net, hwsim_net_id); - hwsim_net->netgroup = hwsim_netgroup++; + hwsim_net->netgroup = ida_simple_get(&hwsim_netgroup_ida, + 0, 0, GFP_KERNEL); + return hwsim_net->netgroup >= 0 ? 0 : -ENOMEM; } static inline u32 hwsim_net_get_wmediumd(struct net *net) @@ -3507,9 +3509,7 @@ failure: static __net_init int hwsim_init_net(struct net *net) { - hwsim_net_set_netgroup(net); - - return 0; + return hwsim_net_set_netgroup(net); } static void __net_exit hwsim_exit_net(struct net *net) @@ -3532,6 +3532,8 @@ static void __net_exit hwsim_exit_net(struct net *net) queue_work(hwsim_wq, &data->destroy_work); } spin_unlock_bh(&hwsim_radio_lock); + + ida_simple_remove(&hwsim_netgroup_ida, hwsim_net_get_netgroup(net)); } static struct pernet_operations hwsim_net_ops = { -- 2.7.4