69 lines
2.2 KiB
Diff
69 lines
2.2 KiB
Diff
From de690194a7a7cd35cd96bb30fd4a709567239146 Mon Sep 17 00:00:00 2001
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Message-Id: <de690194a7a7cd35cd96bb30fd4a709567239146.1601675152.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Wed, 31 Aug 2016 17:54:09 +0200
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Subject: [PATCH 203/333] net: add a lock around icmp_sk()
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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It looks like the this_cpu_ptr() access in icmp_sk() is protected with
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local_bh_disable(). To avoid missing serialization in -RT I am adding
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here a local lock. No crash has been observed, this is just precaution.
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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net/ipv4/icmp.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
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index 4efa5e33513e..de67d595e298 100644
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--- a/net/ipv4/icmp.c
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+++ b/net/ipv4/icmp.c
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@@ -77,6 +77,7 @@
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#include <linux/string.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/slab.h>
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+#include <linux/locallock.h>
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#include <net/snmp.h>
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#include <net/ip.h>
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#include <net/route.h>
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@@ -204,6 +205,8 @@ static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
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*
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* On SMP we have one ICMP socket per-cpu.
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*/
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+static DEFINE_LOCAL_IRQ_LOCK(icmp_sk_lock);
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+
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static struct sock *icmp_sk(struct net *net)
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{
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return *this_cpu_ptr(net->ipv4.icmp_sk);
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@@ -214,12 +217,16 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
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{
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struct sock *sk;
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+ if (!local_trylock(icmp_sk_lock))
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+ return NULL;
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+
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sk = icmp_sk(net);
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if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
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/* This can happen if the output path signals a
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* dst_link_failure() for an outgoing ICMP packet.
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*/
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+ local_unlock(icmp_sk_lock);
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return NULL;
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}
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return sk;
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@@ -228,6 +235,7 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
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static inline void icmp_xmit_unlock(struct sock *sk)
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{
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spin_unlock(&sk->sk_lock.slock);
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+ local_unlock(icmp_sk_lock);
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}
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int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
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--
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2.17.1
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