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-rw-r--r--debian/patches-rt/0203-net-add-a-lock-around-icmp_sk.patch65
1 files changed, 65 insertions, 0 deletions
diff --git a/debian/patches-rt/0203-net-add-a-lock-around-icmp_sk.patch b/debian/patches-rt/0203-net-add-a-lock-around-icmp_sk.patch
new file mode 100644
index 000000000..fa2ad051e
--- /dev/null
+++ b/debian/patches-rt/0203-net-add-a-lock-around-icmp_sk.patch
@@ -0,0 +1,65 @@
+From 95179968fe9e7b7b6484facb14b8ac985cc0d779 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 31 Aug 2016 17:54:09 +0200
+Subject: [PATCH 203/347] net: add a lock around icmp_sk()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+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(+)
+
+diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
+index fe10a565b7d8..d35719e08aef 100644
+--- 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_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);
+@@ -214,12 +217,16 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
+ {
+ struct sock *sk;
+
++ if (!local_trylock(icmp_sk_lock))
++ return NULL;
++
+ 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);
+ return NULL;
+ }
+ return sk;
+@@ -228,6 +235,7 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
+ static inline void icmp_xmit_unlock(struct sock *sk)
+ {
+ spin_unlock(&sk->sk_lock.slock);
++ local_unlock(icmp_sk_lock);
+ }
+
+ int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
+--
+2.36.1
+