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tipc: Fix tipc_sk_reinit handling of -EAGAIN

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In 9dbbfb0ab6680c6a85609041011484e6658e7d3c function tipc_sk_reinit
had additional logic added to loop in the event that function
rhashtable_walk_next() returned -EAGAIN. No worries.

However, if rhashtable_walk_start returns -EAGAIN, it does "continue",
and therefore skips the call to rhashtable_walk_stop(). That has
the effect of calling rcu_read_lock() without its paired call to
rcu_read_unlock(). Since rcu_read_lock() may be nested, the problem
may not be apparent for a while, especially since resize events may
be rare. But the comments to rhashtable_walk_start() state:

 * ...Note that we take the RCU lock in all
 * cases including when we return an error.  So you must always call
 * rhashtable_walk_stop to clean up.

This patch replaces the continue with a goto and label to ensure a
matching call to rhashtable_walk_stop().

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Bob Peterson 2017-08-23 10:43:02 -04:00 committed by David S. Miller
parent e58f95831e
commit 6c7e983b22
1 changed files with 3 additions and 3 deletions
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6
net/tipc/socket.c
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@ -2255,8 +2255,8 @@ void tipc_sk_reinit(struct net *net)
do {
tsk = ERR_PTR(rhashtable_walk_start(&iter));
if (tsk)
continue;
if (IS_ERR(tsk))
goto walk_stop;
while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) {
spin_lock_bh(&tsk->sk.sk_lock.slock);
@ -2265,7 +2265,7 @@ void tipc_sk_reinit(struct net *net)
msg_set_orignode(msg, tn->own_addr);
spin_unlock_bh(&tsk->sk.sk_lock.slock);
}
walk_stop:
rhashtable_walk_stop(&iter);
} while (tsk == ERR_PTR(-EAGAIN));
}