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From: Amol Grover <frextrite@gmail.com>
To: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	"J . Bruce Fields" <bfields@fieldses.org>,
	Chuck Lever <chuck.lever@oracle.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: linux-nfs@vger.kernel.org,
	"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] sunrpc: Pass lockdep expression to RCU lists
Date: Wed, 19 Feb 2020 15:05:05 +0530	[thread overview]
Message-ID: <20200219093504.16290-1-frextrite@gmail.com> (raw)

detail->hash_table[] is traversed using hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of detail->hash_lock.

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

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

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index f740cb51802a..5db5f5b94726 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -97,7 +97,8 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
 	spin_lock(&detail->hash_lock);
 
 	/* check if entry appeared while we slept */
-	hlist_for_each_entry_rcu(tmp, head, cache_list) {
+	hlist_for_each_entry_rcu(tmp, head, cache_list,
+				 lockdep_is_held(&detail->hash_lock)) {
 		if (detail->match(tmp, key)) {
 			if (cache_is_expired(detail, tmp)) {
 				hlist_del_init_rcu(&tmp->cache_list);
-- 
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: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	"J . Bruce Fields" <bfields@fieldses.org>,
	Chuck Lever <chuck.lever@oracle.com>,
	"David S . Miller" <davem@davemloft.net>,
	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>,
	linux-nfs@vger.kernel.org, netdev@vger.kernel.org,
	Amol Grover <frextrite@gmail.com>
Subject: [PATCH] sunrpc: Pass lockdep expression to RCU lists
Date: Wed, 19 Feb 2020 15:05:05 +0530	[thread overview]
Message-ID: <20200219093504.16290-1-frextrite@gmail.com> (raw)

detail->hash_table[] is traversed using hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of detail->hash_lock.

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

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

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index f740cb51802a..5db5f5b94726 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -97,7 +97,8 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
 	spin_lock(&detail->hash_lock);
 
 	/* check if entry appeared while we slept */
-	hlist_for_each_entry_rcu(tmp, head, cache_list) {
+	hlist_for_each_entry_rcu(tmp, head, cache_list,
+				 lockdep_is_held(&detail->hash_lock)) {
 		if (detail->match(tmp, key)) {
 			if (cache_is_expired(detail, tmp)) {
 				hlist_del_init_rcu(&tmp->cache_list);
-- 
2.24.1


             reply	other threads:[~2020-02-19  9:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-19  9:35 Amol Grover [this message]
2020-02-19  9:35 ` [PATCH] sunrpc: Pass lockdep expression to RCU lists Amol Grover
2020-03-03 16:37 ` [Linux-kernel-mentees] " J . Bruce Fields
2020-03-03 16:37   ` J . Bruce Fields

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