linux-kernel - [PATCH] afs: Fix missing/incorrect unlocking of RCU read lock

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Message-ID: <2929034.1705508082@warthog.procyon.org.uk>
Date: Wed, 17 Jan 2024 16:14:42 +0000
From: David Howells <dhowells@...hat.com>
To: Marc Dionne <marc.dionne@...istor.com>
cc: dhowells@...hat.com, linux-afs@...ts.infradead.org,
    linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] afs: Fix missing/incorrect unlocking of RCU read lock

In afs_proc_addr_prefs_show(), we need to unlock the RCU read lock in both
places before returning (and not lock it again).

Fixes: f94f70d39cc2 ("afs: Provide a way to configure address priorities")
Reported-by: Marc Dionne <marc.dionne@...istor.com>
Signed-off-by: David Howells <dhowells@...hat.com>
cc: linux-afs@...ts.infradead.org
cc: linux-fsdevel@...r.kernel.org
---
 fs/afs/proc.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index 3bd02571f30d..15eab053af6d 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -166,7 +166,7 @@ static int afs_proc_addr_prefs_show(struct seq_file *m, void *v)
 
 	if (!preflist) {
 		seq_puts(m, "NO PREFS\n");
-		return 0;
+		goto out;
 	}
 
 	seq_printf(m, "PROT SUBNET                                      PRIOR (v=%u n=%u/%u/%u)\n",
@@ -191,7 +191,8 @@ static int afs_proc_addr_prefs_show(struct seq_file *m, void *v)
 		}
 	}
 
-	rcu_read_lock();
+out:
+	rcu_read_unlock();
 	return 0;
 }