4.4.21-rt31-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
net/ipv4/icmp.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 74314d95d0f8..ff2593269089 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -78,6 +78,7 @@
#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>
@@ -205,6 +206,8 @@ static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
*
* 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);
@@ -216,12 +219,14 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
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;
}
@@ -231,6 +236,7 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
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;
@@ -359,6 +365,7 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
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,
@@ -381,6 +388,7 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
skb->ip_summed = CHECKSUM_NONE;
ip_push_pending_frames(sk, fl4);
}
+ local_unlock(icmp_sk_lock);
}
/*
--
2.8.1
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