[PATCH net] sctp: fix rcu usage on proc listing

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

commit 39f66a7dce32 ("sctp: apply rhashtable api to sctp procfs")
removed a rcu_read_lock() too much at sctp_remaddr_seq_show().

Fixes: 39f66a7dce32 ("sctp: apply rhashtable api to sctp procfs")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 net/sctp/proc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index dfa7eeccb5373053f460f1026a58e4a2ba015a69..4fdf4387910696492ba568b1096dd12e8e7221e2 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c

@@ -491,6 +491,7 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 	tsp = (struct sctp_transport *)v;
 	assoc = tsp->asoc;
 
+	rcu_read_lock();
 	list_for_each_entry_rcu(tsp, &assoc->peer.transport_addr_list,
 				transports) {
 		if (tsp->dead)

@@ -543,6 +544,7 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 
 		seq_printf(seq, "\n");
 	}
+	rcu_read_unlock();
 
 	return 0;
 }

-- 
2.5.0

[just cc'ing linux-sctp@vger.kernel.org]

On Tue, Jan 19, 2016 at 07:59:03PM -0200, Marcelo Ricardo Leitner wrote:

On Tue, Jan 19, 2016 at 08:02:30PM -0200, Marcelo Ricardo Leitner wrote:

quoted

--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c

@@ -491,6 +491,7 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 	tsp = (struct sctp_transport *)v;
 	assoc = tsp->asoc;
 
+	rcu_read_lock();

should have used rcu_read_lock_bh() here, will send a v2 tomorrow.

quoted

 	list_for_each_entry_rcu(tsp, &assoc->peer.transport_addr_list,
 				transports) {
 		if (tsp->dead)

@@ -543,6 +544,7 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 
 		seq_printf(seq, "\n");
 	}
+	rcu_read_unlock();
 
 	return 0;
 }

-- 
2.5.0

On Tue, Jan 19, 2016 at 11:07:20PM -0200, Marcelo Ricardo Leitner wrote:

On Tue, Jan 19, 2016 at 08:02:30PM -0200, Marcelo Ricardo Leitner wrote:

quoted

quoted

--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c

@@ -491,6 +491,7 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 	tsp = (struct sctp_transport *)v;
 	assoc = tsp->asoc;
 
+	rcu_read_lock();

should have used rcu_read_lock_bh() here, will send a v2 tomorrow.

Please just drop this one, no change is actually needed.
rhashtable_walk_start() already puts the rcu_read_lock() in there and
disabling bh is not necessary. Thanks.

quoted

quoted

 	list_for_each_entry_rcu(tsp, &assoc->peer.transport_addr_list,
 				transports) {
 		if (tsp->dead)

@@ -543,6 +544,7 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v)
 
 		seq_printf(seq, "\n");
 	}
+	rcu_read_unlock();
 
 	return 0;
 }

-- 
2.5.0

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