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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc: SteveW@ACM.org, davem@davemloft.net, dipankar@in.ibm.com
Subject: dn_route.c momentarily exiting RCU read-side critical section
Date: Mon, 29 Oct 2007 14:15:40 -0700	[thread overview]
Message-ID: <20071029211540.GA12893@linux.vnet.ibm.com> (raw)

Hello!

net/decnet/dn_route.c in dn_rt_cache_get_next() is as follows:

static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
{
	struct dn_rt_cache_iter_state *s = rcu_dereference(seq->private);

	rt = rt->u.dst.dn_next;
	while(!rt) {
		rcu_read_unlock_bh();
		if (--s->bucket < 0)
			break;

...  But what happens if seq->private is freed up right here?
...  Or what prevents this from happening?

		rcu_read_lock_bh();
		rt = dn_rt_hash_table[s->bucket].chain;
	}
	return rt;
}

Similar code is in rt_cache_get_next().

So, what am I missing here?

						Thanx, Paul

             reply	other threads:[~2007-10-29 21:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-29 21:15 Paul E. McKenney [this message]
2007-10-30  8:10 ` dn_route.c momentarily exiting RCU read-side critical section David Miller
2007-10-30 15:12   ` Paul E. McKenney
2007-11-05 11:53     ` Herbert Xu
2007-11-05 16:12       ` Paul E. McKenney
2007-11-05 23:51         ` Herbert Xu

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