75 lines
2.5 KiB
Diff
75 lines
2.5 KiB
Diff
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From 5e6729ef1e7a1e3136965debb2f302c6b5570c45 Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Mon, 21 Aug 2017 15:09:13 +0200
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Subject: [PATCH 335/365] net: take the tcp_sk_lock lock with BH disabled
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Lockdep may complain about an unsafe locking scenario:
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| CPU0 CPU1
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| ---- ----
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| lock((tcp_sk_lock).lock);
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| lock(&per_cpu(local_softirq_locks[i], __cpu).lock);
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| lock((tcp_sk_lock).lock);
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| lock(&per_cpu(local_softirq_locks[i], __cpu).lock);
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in the call paths:
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do_current_softirqs -> tcp_v4_send_ack()
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vs
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tcp_v4_send_reset -> do_current_softirqs().
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This should not happen since local_softirq_locks is per CPU. Reversing
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the order makes lockdep happy.
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Change-Id: I4b773f3dd84f8bda96067e319cfd27469f3c5dfe
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Reported-by: Jacek Konieczny <jajcus@jajcus.net>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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net/ipv4/tcp_ipv4.c | 8 ++++----
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1 file changed, 4 insertions(+), 4 deletions(-)
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diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
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index 89d986d0d77d..736bd9f45c7f 100644
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--- a/net/ipv4/tcp_ipv4.c
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+++ b/net/ipv4/tcp_ipv4.c
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@@ -705,8 +705,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
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arg.tos = ip_hdr(skb)->tos;
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arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
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- local_lock(tcp_sk_lock);
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local_bh_disable();
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+ local_lock(tcp_sk_lock);
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ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
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skb, &TCP_SKB_CB(skb)->header.h4.opt,
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ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
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@@ -714,8 +714,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
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__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
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__TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
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- local_bh_enable();
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local_unlock(tcp_sk_lock);
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+ local_bh_enable();
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#ifdef CONFIG_TCP_MD5SIG
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out:
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@@ -793,16 +793,16 @@ static void tcp_v4_send_ack(const struct sock *sk,
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arg.bound_dev_if = oif;
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arg.tos = tos;
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arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
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- local_lock(tcp_sk_lock);
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local_bh_disable();
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+ local_lock(tcp_sk_lock);
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ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
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skb, &TCP_SKB_CB(skb)->header.h4.opt,
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ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
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&arg, arg.iov[0].iov_len);
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__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
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- local_bh_enable();
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local_unlock(tcp_sk_lock);
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+ local_bh_enable();
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}
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static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
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--
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2.28.0
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