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From: Amol Grover <frextrite@gmail.com>
To: Johannes Berg <johannes@sipsolutions.net>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
	netdev@vger.kernel.org, linux-wireless@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] cfg80211: Pass lockdep expression to RCU lists
Date: Wed, 19 Feb 2020 14:41:04 +0530	[thread overview]
Message-ID: <20200219091102.10709-1-frextrite@gmail.com> (raw)

rdev->sched_scan_req_list maybe traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of rtnl_mutex.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
 net/wireless/scan.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index aef240fdf8df..7f1af8f347b1 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -556,9 +556,8 @@ cfg80211_find_sched_scan_req(struct cfg80211_registered_device *rdev, u64 reqid)
 {
 	struct cfg80211_sched_scan_request *pos;
 
-	WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held());
-
-	list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list) {
+	list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list,
+				lockdep_rtnl_is_held()) {
 		if (pos->reqid == reqid)
 			return pos;
 	}
-- 
2.24.1

_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

WARNING: multiple messages have this Message-ID (diff)
From: Amol Grover <frextrite@gmail.com>
To: Johannes Berg <johannes@sipsolutions.net>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: linux-wireless@vger.kernel.org, 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] cfg80211: Pass lockdep expression to RCU lists
Date: Wed, 19 Feb 2020 14:41:04 +0530	[thread overview]
Message-ID: <20200219091102.10709-1-frextrite@gmail.com> (raw)

rdev->sched_scan_req_list maybe traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of rtnl_mutex.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
 net/wireless/scan.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index aef240fdf8df..7f1af8f347b1 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -556,9 +556,8 @@ cfg80211_find_sched_scan_req(struct cfg80211_registered_device *rdev, u64 reqid)
 {
 	struct cfg80211_sched_scan_request *pos;
 
-	WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held());
-
-	list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list) {
+	list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list,
+				lockdep_rtnl_is_held()) {
 		if (pos->reqid == reqid)
 			return pos;
 	}
-- 
2.24.1


             reply	other threads:[~2020-02-19  9:12 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-19  9:11 Amol Grover [this message]
2020-02-19  9:11 ` [PATCH] cfg80211: Pass lockdep expression to RCU lists Amol Grover
2020-02-19  9:13 ` [Linux-kernel-mentees] " Johannes Berg
2020-02-19  9:13   ` Johannes Berg
2020-02-19 12:47   ` [Linux-kernel-mentees] " Paul E. McKenney
2020-02-19 12:47     ` Paul E. McKenney
2020-02-19 21:27   ` [Linux-kernel-mentees] " Arend Van Spriel via Linux-kernel-mentees
2020-02-19 21:27     ` Arend Van Spriel
2020-02-19 21:29     ` [Linux-kernel-mentees] " Johannes Berg
2020-02-19 21:29       ` Johannes Berg
2020-02-19 21:33       ` [Linux-kernel-mentees] " Arend Van Spriel via Linux-kernel-mentees
2020-02-19 21:33         ` Arend Van Spriel

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