From: Amol Grover <frextrite@gmail.com>
To: Eric Dumazet <edumazet@google.com>,
"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] tcp: Pass lockdep expression to RCU lists
Date: Wed, 19 Feb 2020 15:35:46 +0530 [thread overview]
Message-ID: <20200219100545.27397-1-frextrite@gmail.com> (raw)
tcp_cong_list is traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of tcp_cong_list_lock.
Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
net/ipv4/tcp_cong.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 3737ec096650..8d4446ed309e 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -25,7 +25,8 @@ static struct tcp_congestion_ops *tcp_ca_find(const char *name)
{
struct tcp_congestion_ops *e;
- list_for_each_entry_rcu(e, &tcp_cong_list, list) {
+ list_for_each_entry_rcu(e, &tcp_cong_list, list,
+ lockdep_is_held(&tcp_cong_list_lock)) {
if (strcmp(e->name, name) == 0)
return e;
}
@@ -55,7 +56,8 @@ struct tcp_congestion_ops *tcp_ca_find_key(u32 key)
{
struct tcp_congestion_ops *e;
- list_for_each_entry_rcu(e, &tcp_cong_list, list) {
+ list_for_each_entry_rcu(e, &tcp_cong_list, list,
+ lockdep_is_held(&tcp_cong_list_lock)) {
if (e->key == key)
return e;
}
@@ -317,7 +319,8 @@ int tcp_set_allowed_congestion_control(char *val)
}
/* pass 2 clear old values */
- list_for_each_entry_rcu(ca, &tcp_cong_list, list)
+ list_for_each_entry_rcu(ca, &tcp_cong_list, list,
+ lockdep_is_held(&tcp_cong_list_lock))
ca->flags &= ~TCP_CONG_NON_RESTRICTED;
/* pass 3 mark as allowed */
--
2.24.1
next reply other threads:[~2020-02-19 10:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 10:05 Amol Grover [this message]
2020-02-19 19:35 ` [PATCH] tcp: Pass lockdep expression to RCU lists Eric Dumazet
2020-02-20 3:47 ` Amol Grover
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