blob: 5734d88ef3dab2d760ce53c562816f2183f29d16 [file] [log] [blame]
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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 <bigeasy@linutronix.de>
---
net/ipv4/icmp.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -77,6 +77,7 @@
#include <linux/string.h>
#include <linux/netfilter_ipv4.h>
#include <linux/slab.h>
+#include <linux/locallock.h>
#include <net/snmp.h>
#include <net/ip.h>
#include <net/route.h>
@@ -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);
@@ -215,12 +218,14 @@ static inline struct sock *icmp_xmit_loc
local_bh_disable();
+ local_lock(icmp_sk_lock);
sk = icmp_sk(net);
if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
/* This can happen if the output path signals a
* dst_link_failure() for an outgoing ICMP packet.
*/
+ local_unlock(icmp_sk_lock);
local_bh_enable();
return NULL;
}
@@ -230,6 +235,7 @@ static inline struct sock *icmp_xmit_loc
static inline void icmp_xmit_unlock(struct sock *sk)
{
spin_unlock_bh(&sk->sk_lock.slock);
+ local_unlock(icmp_sk_lock);
}
int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
@@ -358,6 +364,7 @@ static void icmp_push_reply(struct icmp_
struct sock *sk;
struct sk_buff *skb;
+ local_lock(icmp_sk_lock);
sk = icmp_sk(dev_net((*rt)->dst.dev));
if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
icmp_param->data_len+icmp_param->head_len,
@@ -380,6 +387,7 @@ static void icmp_push_reply(struct icmp_
skb->ip_summed = CHECKSUM_NONE;
ip_push_pending_frames(sk, fl4);
}
+ local_unlock(icmp_sk_lock);
}
/*