From: "Michał Mirosław" <mirqus@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com,
tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
David Miller <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH tip/core/rcu 05/13] net: add checking to rcu_dereference() primitives
Date: Sun, 14 Feb 2010 09:34:43 +0100 [thread overview]
Message-ID: <e2d7436a1002140034h74617164p1a5dc90df3587095@mail.gmail.com> (raw)
In-Reply-To: <1265948152.2891.25.camel@edumazet-laptop>
2010/2/12 Eric Dumazet <eric.dumazet@gmail.com>:
> Le jeudi 11 février 2010 à 16:00 -0800, Paul E. McKenney a écrit :
[...]
>> @@ -1654,12 +1654,12 @@ static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
>>
>> for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
>> rcu_read_lock_bh();
>> - rt = dn_rt_hash_table[s->bucket].chain;
>> + rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
>> if (rt)
>> break;
>> rcu_read_unlock_bh();
>> }
>> - return rcu_dereference(rt);
>> + return rt;
>> }
Isn't there a bug? Looks like data pointed to by rt should be
protected by RCU, but the rcu_read_lock is withdrawn before access.
Best Regards,
Michał Mirosław
next prev parent reply other threads:[~2010-02-14 8:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100212000016.GA25781@linux.vnet.ibm.com>
[not found] ` <1265932839-25899-5-git-send-email-paulmck@linux.vnet.ibm.com>
2010-02-12 4:15 ` [PATCH tip/core/rcu 05/13] net: add checking to rcu_dereference() primitives Eric Dumazet
2010-02-14 8:23 ` Ingo Molnar
2010-02-15 7:18 ` David Miller
2010-02-14 8:34 ` Michał Mirosław [this message]
2010-02-14 8:50 ` Eric Dumazet
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