From: Amol Grover <frextrite@gmail.com>
To: "David S . Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH] ip6mr: Fix RCU list debugging warning
Date: Sat, 22 Feb 2020 22:27:27 +0530 [thread overview]
Message-ID: <20200222165726.9330-1-frextrite@gmail.com> (raw)
ip6mr_for_each_table() macro uses list_for_each_entry_rcu()
for traversing outside an RCU read side critical section
but under the protection of rtnl_mutex. Hence add the
corresponding lockdep expression to silence the following
false-positive warnings:
[ 4.319479] =============================
[ 4.319480] WARNING: suspicious RCU usage
[ 4.319482] 5.5.4-stable #17 Tainted: G E
[ 4.319483] -----------------------------
[ 4.319485] net/ipv6/ip6mr.c:1243 RCU-list traversed in non-reader section!!
[ 4.456831] =============================
[ 4.456832] WARNING: suspicious RCU usage
[ 4.456834] 5.5.4-stable #17 Tainted: G E
[ 4.456835] -----------------------------
[ 4.456837] net/ipv6/ip6mr.c:1582 RCU-list traversed in non-reader section!!
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
net/ipv6/ip6mr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index bfa49ff70531..d6483926f449 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -97,7 +97,8 @@ static void ipmr_expire_process(struct timer_list *t);
#ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
#define ip6mr_for_each_table(mrt, net) \
- list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list)
+ list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list, \
+ lockdep_rtnl_is_held())
static struct mr_table *ip6mr_mr_table_iter(struct net *net,
struct mr_table *mrt)
--
2.24.1
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https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
WARNING: multiple messages have this Message-ID (diff)
From: Amol Grover <frextrite@gmail.com>
To: "David S . Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>
Cc: linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
Joel Fernandes <joel@joelfernandes.org>,
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
netdev@vger.kernel.org, Amol Grover <frextrite@gmail.com>
Subject: [PATCH] ip6mr: Fix RCU list debugging warning
Date: Sat, 22 Feb 2020 22:27:27 +0530 [thread overview]
Message-ID: <20200222165726.9330-1-frextrite@gmail.com> (raw)
ip6mr_for_each_table() macro uses list_for_each_entry_rcu()
for traversing outside an RCU read side critical section
but under the protection of rtnl_mutex. Hence add the
corresponding lockdep expression to silence the following
false-positive warnings:
[ 4.319479] =============================
[ 4.319480] WARNING: suspicious RCU usage
[ 4.319482] 5.5.4-stable #17 Tainted: G E
[ 4.319483] -----------------------------
[ 4.319485] net/ipv6/ip6mr.c:1243 RCU-list traversed in non-reader section!!
[ 4.456831] =============================
[ 4.456832] WARNING: suspicious RCU usage
[ 4.456834] 5.5.4-stable #17 Tainted: G E
[ 4.456835] -----------------------------
[ 4.456837] net/ipv6/ip6mr.c:1582 RCU-list traversed in non-reader section!!
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
net/ipv6/ip6mr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index bfa49ff70531..d6483926f449 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -97,7 +97,8 @@ static void ipmr_expire_process(struct timer_list *t);
#ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
#define ip6mr_for_each_table(mrt, net) \
- list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list)
+ list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list, \
+ lockdep_rtnl_is_held())
static struct mr_table *ip6mr_mr_table_iter(struct net *net,
struct mr_table *mrt)
--
2.24.1
next reply other threads:[~2020-02-22 16:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-22 16:57 Amol Grover [this message]
2020-02-22 16:57 ` [PATCH] ip6mr: Fix RCU list debugging warning Amol Grover
2020-02-24 21:19 ` [Linux-kernel-mentees] " David Miller
2020-02-24 21:19 ` David Miller
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