From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Julia Cartwright <julia@ni.com>,
Daniel Wagner <daniel.wagner@siemens.com>,
tom.zanussi@linux.intel.com, Alex Shi <alex.shi@linaro.org>,
Jacek Konieczny <jajcus@jajcus.net>
Subject: [PATCH RT 07/15] net: take the tcp_sk_lock lock with BH disabled
Date: Fri, 01 Dec 2017 19:01:56 -0500 [thread overview]
Message-ID: <20171202000427.724064752@goodmis.org> (raw)
In-Reply-To: 20171202000149.842718953@goodmis.org
[-- Attachment #1: 0007-net-take-the-tcp_sk_lock-lock-with-BH-disabled.patch --]
[-- Type: text/plain, Size: 2312 bytes --]
4.9.65-rt57-rc2 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Lockdep may complain about an unsafe locking scenario:
| CPU0 CPU1
| ---- ----
| lock((tcp_sk_lock).lock);
| lock(&per_cpu(local_softirq_locks[i], __cpu).lock);
| lock((tcp_sk_lock).lock);
| lock(&per_cpu(local_softirq_locks[i], __cpu).lock);
in the call paths:
do_current_softirqs -> tcp_v4_send_ack()
vs
tcp_v4_send_reset -> do_current_softirqs().
This should not happen since local_softirq_locks is per CPU. Reversing
the order makes lockdep happy.
Reported-by: Jacek Konieczny <jajcus@jajcus.net>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
net/ipv4/tcp_ipv4.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 3336e1534bc5..3b7298459c87 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -698,8 +698,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
arg.tos = ip_hdr(skb)->tos;
- local_lock(tcp_sk_lock);
local_bh_disable();
+ local_lock(tcp_sk_lock);
ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
skb, &TCP_SKB_CB(skb)->header.h4.opt,
ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
@@ -707,8 +707,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
__TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
- local_bh_enable();
local_unlock(tcp_sk_lock);
+ local_bh_enable();
#ifdef CONFIG_TCP_MD5SIG
out:
@@ -784,16 +784,16 @@ static void tcp_v4_send_ack(struct net *net,
if (oif)
arg.bound_dev_if = oif;
arg.tos = tos;
- local_lock(tcp_sk_lock);
local_bh_disable();
+ local_lock(tcp_sk_lock);
ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
skb, &TCP_SKB_CB(skb)->header.h4.opt,
ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
&arg, arg.iov[0].iov_len);
__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
- local_bh_enable();
local_unlock(tcp_sk_lock);
+ local_bh_enable();
}
static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
--
2.13.2
next prev parent reply other threads:[~2017-12-02 0:04 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-02 0:01 [PATCH RT 00/15] Linux 4.9.65-rt57-rc2 Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 01/15] Revert "memcontrol: Prevent scheduling while atomic in cgroup code" Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 02/15] Revert "fs: jbd2: pull your plug when waiting for space" Steven Rostedt
2017-12-04 8:37 ` Sebastian Andrzej Siewior
2017-12-08 18:13 ` Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 03/15] rtmutex: Fix lock stealing logic Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 04/15] cpu_pm: replace raw_notifier to atomic_notifier Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 05/15] PM / CPU: replace raw_notifier with atomic_notifier (fixup) Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 06/15] kernel/hrtimer: migrate deferred timer on CPU down Steven Rostedt
2017-12-02 0:01 ` Steven Rostedt [this message]
2017-12-02 0:01 ` [PATCH RT 08/15] kernel/hrtimer: dont wakeup a process while holding the hrtimer base lock Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 09/15] kernel/hrtimer/hotplug: dont wake ktimersoftd " Steven Rostedt
2017-12-02 0:01 ` [PATCH RT 10/15] Bluetooth: avoid recursive locking in hci_send_to_channel() Steven Rostedt
2017-12-02 0:02 ` [PATCH RT 11/15] iommu/amd: Use raw_cpu_ptr() instead of get_cpu_ptr() for ->flush_queue Steven Rostedt
2017-12-02 0:02 ` Steven Rostedt
2017-12-02 0:02 ` [PATCH RT 12/15] rt/locking: allow recursive local_trylock() Steven Rostedt
2017-12-02 0:02 ` [PATCH RT 13/15] locking/rtmutex: dont drop the wait_lock twice Steven Rostedt
2017-12-02 0:02 ` [PATCH RT 14/15] net: use trylock in icmp_sk Steven Rostedt
2017-12-02 0:02 ` [PATCH RT 15/15] Linux 4.9.65-rt57-rc2 Steven Rostedt
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