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: netdev@vger.kernel.org, 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>,
Amol Grover <frextrite@gmail.com>
Subject: [PATCH net 2/2 RESEND] ipmr: Add lockdep expression to ipmr_for_each_table macro
Date: Sat, 9 May 2020 12:52:44 +0530 [thread overview]
Message-ID: <20200509072243.3141-2-frextrite@gmail.com> (raw)
In-Reply-To: <20200509072243.3141-1-frextrite@gmail.com>
ipmr_for_each_table() uses list_for_each_entry_rcu() for
traversing outside of an RCU read-side critical section but
under the protection of pernet_ops_rwsem. Hence add the
corresponding lockdep expression to silence the following
false-positive warning at boot:
[ 0.645292] =============================
[ 0.645294] WARNING: suspicious RCU usage
[ 0.645296] 5.5.4-stable #17 Not tainted
[ 0.645297] -----------------------------
[ 0.645299] net/ipv4/ipmr.c:136 RCU-list traversed in non-reader section!!
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
net/ipv4/ipmr.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 99c864eb6e34..950ffe9943da 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -109,9 +109,10 @@ static void mroute_clean_tables(struct mr_table *mrt, int flags);
static void ipmr_expire_process(struct timer_list *t);
#ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
-#define ipmr_for_each_table(mrt, net) \
- list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list, \
- lockdep_rtnl_is_held())
+#define ipmr_for_each_table(mrt, net) \
+ list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list, \
+ lockdep_rtnl_is_held() || \
+ lockdep_is_held(&pernet_ops_rwsem))
static struct mr_table *ipmr_mr_table_iter(struct net *net,
struct mr_table *mrt)
--
2.24.1
next prev parent reply other threads:[~2020-05-09 7:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-09 7:22 [PATCH net 1/2 RESEND] ipmr: Fix RCU list debugging warning Amol Grover
2020-05-09 7:22 ` Amol Grover [this message]
2020-05-09 21:19 ` [PATCH net 2/2 RESEND] ipmr: Add lockdep expression to ipmr_for_each_table macro Jakub Kicinski
2020-05-12 5:17 ` Madhuparna Bhowmik
2020-05-12 16:32 ` Jakub Kicinski
2020-05-13 5:34 ` Madhuparna Bhowmik
2020-05-12 17:17 ` Amol Grover
2020-05-12 21:59 ` Jakub Kicinski
2020-05-13 11:54 ` Stephen Rothwell
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