From: Fabio Estevam <festevam@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Francois Romieu <romieu@fr.zoreil.com>,
David Miller <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Chuck Lever <chuck.lever@oracle.com>,
Trond Myklebust <trond.myklebust@primarydata.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH net-next] tcp: fix lockdep splat in tcp_snd_una_update()
Date: Tue, 3 May 2016 22:26:50 -0300 [thread overview]
Message-ID: <CAOMZO5AL6Vd7jdFWdSb_TokSNWW7x19TSO__w22B6k7wr6VPxw@mail.gmail.com> (raw)
In-Reply-To: <1462319763.5535.329.camel@edumazet-glaptop3.roam.corp.google.com>
On Tue, May 3, 2016 at 8:56 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> tcp_snd_una_update() and tcp_rcv_nxt_update() call
> u64_stats_update_begin() either from process context or BH handler.
>
> This triggers a lockdep splat on 32bit & SMP builds.
>
> We could add u64_stats_update_begin_bh() variant but this would
> slow down 32bit builds with useless local_disable_bh() and
> local_enable_bh() pairs, since we own the socket lock at this point.
>
> I add sock_owned_by_me() helper to have proper lockdep support
> even on 64bit builds, and new u64_stats_update_begin_raw()
> and u64_stats_update_end_raw methods.
>
> Fixes: c10d9310edf5 ("tcp: do not assume TCP code is non preemptible")
> Reported-by: Fabio Estevam <festevam@gmail.com>
> Diagnosed-by: Francois Romieu <romieu@fr.zoreil.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Thanks for the fix, Eric and Francois! This allows me to do NFS boot again:
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
next prev parent reply other threads:[~2016-05-04 1:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-29 23:18 Cannot use NFS with linux-next 20160429 Fabio Estevam
2016-05-01 19:52 ` Chuck Lever
2016-05-03 19:37 ` Fabio Estevam
2016-05-03 22:31 ` Francois Romieu
2016-05-03 22:35 ` Eric Dumazet
2016-05-03 23:56 ` [PATCH net-next] tcp: fix lockdep splat in tcp_snd_una_update() Eric Dumazet
2016-05-04 1:26 ` Fabio Estevam [this message]
2016-05-04 4:54 ` David Miller
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