From: Eric Dumazet <eric.dumazet@gmail.com>
To: Pavel Emelyanov <xemul@parallels.com>
Cc: "Sjur Brændeland" <sjur.brandeland@stericsson.com>,
"levinsasha928@gmail.com" <levinsasha928@gmail.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"davej@redhat.com" <davej@redhat.com>,
"sjurbren@gmail.com" <sjurbren@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH] netns: fix net_alloc_generic()
Date: Thu, 26 Jan 2012 11:51:48 +0100 [thread overview]
Message-ID: <1327575108.2500.24.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> (raw)
In-Reply-To: <4F212E7E.2040801@parallels.com>
Le jeudi 26 janvier 2012 à 14:44 +0400, Pavel Emelyanov a écrit :
> > I believe the problem is in net_namespace infrastructure, not in CAIF.
> >
> > Could you test following patch instead ?
> >
> > [PATCH] netns: fix net_alloc_generic()
> >
> > When a new net namespace is created, we should attach to it a "struct
> > net_generic" with enough slots (even empty), or we can hit the following
> > BUG_ON() :
> >
> > [ 200.752016] kernel BUG at include/net/netns/generic.h:40!
> > ...
> > [ 200.752016] [<ffffffff825c3cea>] ? get_cfcnfg+0x3a/0x180
> > [ 200.752016] [<ffffffff821cf0b0>] ? lockdep_rtnl_is_held+0x10/0x20
> > [ 200.752016] [<ffffffff825c41be>] caif_device_notify+0x2e/0x530
> > [ 200.752016] [<ffffffff810d61b7>] notifier_call_chain+0x67/0x110
> > [ 200.752016] [<ffffffff810d67c1>] raw_notifier_call_chain+0x11/0x20
> > [ 200.752016] [<ffffffff821bae82>] call_netdevice_notifiers+0x32/0x60
> > [ 200.752016] [<ffffffff821c2b26>] register_netdevice+0x196/0x300
> > [ 200.752016] [<ffffffff821c2ca9>] register_netdev+0x19/0x30
> > [ 200.752016] [<ffffffff81c1c67a>] loopback_net_init+0x4a/0xa0
> > [ 200.752016] [<ffffffff821b5e62>] ops_init+0x42/0x180
> > [ 200.752016] [<ffffffff821b600b>] setup_net+0x6b/0x100
> > [ 200.752016] [<ffffffff821b6466>] copy_net_ns+0x86/0x110
> > [ 200.752016] [<ffffffff810d5789>] create_new_namespaces+0xd9/0x190
> >
> > net_alloc_generic() should take into account the maximum index into the
> > ptr array, as a subsystem might use net_generic() anytime.
>
> I'm not sure I understand it correctly, but subsystem can only use the
> net_generic() only (!) after the net_assign_generic() is performed.
Yes, but here, loopback_net_init() calls register_netdev()
So every subsystems _notify are called, even if subsystem _init_net()
was not yet called.
Its a chicken and egg problem.
next prev parent reply other threads:[~2012-01-26 10:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-24 7:30 [PATCH] net: caif: Don't act on notification for non-caif devices Sasha Levin
2012-01-24 10:52 ` Sjur Brændeland
2012-01-24 14:49 ` Sasha Levin
2012-01-24 15:06 ` Sjur Brændeland
2012-01-24 15:23 ` Sasha Levin
2012-01-24 22:27 ` [PATCH net] caif: Fix crash due to uninitialized net name-space Sjur Brændeland
2012-01-24 22:44 ` David Miller
2012-01-25 16:13 ` Sasha Levin
2012-01-25 20:33 ` Sjur Brændeland
2012-01-26 6:14 ` Eric Dumazet
2012-01-26 10:41 ` [PATCH] netns: fix net_alloc_generic() Eric Dumazet
2012-01-26 10:44 ` Pavel Emelyanov
2012-01-26 10:51 ` Eric Dumazet [this message]
2012-01-26 22:57 ` Eric W. Biederman
2012-01-26 23:07 ` David Miller
2012-01-26 23:57 ` Eric W. Biederman
2012-01-27 0:02 ` [PATCH 1/2] netns: Fail conspicously if someone uses net_generic at an inappropriate time Eric W. Biederman
2012-01-27 0:04 ` [PATCH 2/2] net caif: Register properly as a pernet subsystem Eric W. Biederman
2012-01-27 13:24 ` Sasha Levin
2012-01-27 14:48 ` Sjur BRENDELAND
2012-01-28 2:07 ` David Miller
2012-01-28 2:07 ` [PATCH 1/2] netns: Fail conspicously if someone uses net_generic at an inappropriate time David Miller
2012-01-27 6:09 ` [PATCH] netns: fix net_alloc_generic() Eric Dumazet
2012-01-27 6:54 ` Eric W. Biederman
2012-01-27 7:07 ` Eric Dumazet
2012-01-26 14:40 ` Sasha Levin
2012-01-26 18:37 ` David Miller
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