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From: David Miller <davem@redhat.com>
To: eric.dumazet@gmail.com
Cc: mleitner@redhat.com, edumazet@google.com, netdev@vger.kernel.org,
	ycheng@google.com, mattmathis@google.com, cgallek@google.com,
	kafai@fb.com
Subject: Re: [PATCH net-next] tcp: fix a potential deadlock in tcp_get_info()
Date: Fri, 22 May 2015 13:50:42 -0400 (EDT)	[thread overview]
Message-ID: <20150522.135042.1383929510137041615.davem@redhat.com> (raw)
In-Reply-To: <1432270279.4060.128.camel@edumazet-glaptop2.roam.corp.google.com>

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 21 May 2015 21:51:19 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> Taking socket spinlock in tcp_get_info() can deadlock, as
> inet_diag_dump_icsk() holds the &hashinfo->ehash_locks[i],
> while packet processing can use the reverse locking order.
> 
> We could avoid this locking for TCP_LISTEN states, but lockdep would
> certainly get confused as all TCP sockets share same lockdep classes.
 ...
> Lets use u64_sync infrastructure instead. As a bonus, 64bit
> arches get optimized, as these are nop for them.
> 
> Fixes: 0df48c26d841 ("tcp: add tcpi_bytes_acked to tcp_info")
> Signed-off-by: Eric Dumazet <edumazet@google.com>

This bug exists in 'net' so I've applied it there.

Thanks Eric.

  reply	other threads:[~2015-05-22 17:50 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-28 22:28 [PATCH v2 net-next 0/2] tcp: tcp_info extensions Eric Dumazet
2015-04-28 22:28 ` [PATCH v2 net-next 1/2] tcp: add tcpi_bytes_acked to tcp_info Eric Dumazet
2015-04-29 22:12   ` David Miller
2015-04-28 22:28 ` [PATCH v2 net-next 2/2] tcp: add tcpi_bytes_received " Eric Dumazet
2015-04-28 22:56   ` Yuchung Cheng
2015-04-28 23:07     ` Eric Dumazet
2015-04-29 22:12   ` David Miller
2015-05-12 13:08 ` [PATCH v2 net-next 0/2] tcp: tcp_info extensions Marcelo Ricardo Leitner
2015-05-12 20:31   ` Eric Dumazet
2015-05-12 22:21     ` Marcelo Ricardo Leitner
2015-05-20 23:35     ` [PATCH net-next] tcp: add tcpi_segs_in and tcpi_segs_out to tcp_info Eric Dumazet
2015-05-21  0:06       ` Rick Jones
2015-05-21  0:37         ` Eric Dumazet
2015-05-21  0:48           ` Rick Jones
2015-05-21  0:52             ` Eric Dumazet
2015-05-21 12:38               ` Marcelo Ricardo Leitner
2015-05-21 19:41       ` Yuchung Cheng
2015-05-21 20:06         ` Eric Dumazet
2015-05-21 21:53         ` Marcelo Ricardo Leitner
2015-05-22  3:25       ` David Miller
2015-05-22  3:43         ` Eric Dumazet
2015-05-22  4:51           ` [PATCH net-next] tcp: fix a potential deadlock in tcp_get_info() Eric Dumazet
2015-05-22 17:50             ` David Miller [this message]
2015-05-22 17:56               ` Eric Dumazet
2015-05-22 18:03                 ` Eric Dumazet
2015-05-22 18:08                   ` Eric Dumazet
2015-05-22 18:21                     ` David Miller
2015-05-22 18:12                 ` David Miller

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