From: Sebastian Andrzej Siewior Date: Wed, 31 Aug 2016 17:54:09 +0200 Subject: [PATCH] net: add a lock around icmp_sk() It looks like the this_cpu_ptr() access in icmp_sk() is protected with local_bh_disable(). To avoid missing serialization in -RT I am adding here a local lock. No crash has been observed, this is just precaution. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior --- net/ipv4/icmp.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -77,6 +77,7 @@ #include #include #include +#include #include #include #include @@ -204,6 +205,8 @@ static const struct icmp_control icmp_po * * On SMP we have one ICMP socket per-cpu. */ +static DEFINE_LOCAL_IRQ_LOCK(icmp_sk_lock); + static struct sock *icmp_sk(struct net *net) { return *this_cpu_ptr(net->ipv4.icmp_sk); @@ -417,6 +420,7 @@ static void icmp_reply(struct icmp_bxm * /* Needed by both icmp_global_allow and icmp_xmit_lock */ local_bh_disable(); + local_lock(icmp_sk_lock); /* global icmp_msgs_per_sec */ if (!icmpv4_global_allow(net, type, code)) @@ -461,6 +465,7 @@ static void icmp_reply(struct icmp_bxm * out_unlock: icmp_xmit_unlock(sk); out_bh_enable: + local_unlock(icmp_sk_lock); local_bh_enable(); } @@ -673,6 +678,7 @@ void icmp_send(struct sk_buff *skb_in, i /* Needed by both icmp_global_allow and icmp_xmit_lock */ local_bh_disable(); + local_lock(icmp_sk_lock); /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless * incoming dev is loopback. If outgoing dev change to not be @@ -761,6 +767,7 @@ void icmp_send(struct sk_buff *skb_in, i out_unlock: icmp_xmit_unlock(sk); out_bh_enable: + local_unlock(icmp_sk_lock); local_bh_enable(); out:; }