From: Patrick McHardy <kaber@trash•net>
To: "Eric W. Biederman" <ebiederm@xmission•com>
Cc: David Miller <davem@davemloft•net>,
netdev@vger•kernel.org,
Linux Containers <containers@lists•osdl.org>
Subject: Re: [PATCH 2/5] net: Make rtnetlink infrastructure network namespace aware
Date: Sun, 30 Sep 2007 17:39:54 +0200 [thread overview]
Message-ID: <46FFC34A.3020701@trash.net> (raw)
In-Reply-To: <m1myv56vb3.fsf@ebiederm.dsl.xmission.com>
Eric W. Biederman wrote:
> Patrick McHardy <kaber@trash•net> writes:
>
>
>>Maybe I can save you some time: we used to do down_trylock()
>>for the rtnl mutex, so senders would simply return if someone
>>else was already processing the queue *or* the rtnl was locked
>>for some other reason. In the first case the process already
>>processing the queue would also process the new messages, but
>>if it the rtnl was locked for some other reason (for example
>>during module registration) the message would sit in the
>>queue until the next rtnetlink sendmsg call, which is why
>>rtnl_unlock does queue processing. Commit 6756ae4b changed
>>the down_trylock to mutex_lock, so senders will now simply wait
>>until the mutex is released and then call netlink_run_queue
>>themselves. This means its not needed anymore.
>
>
> Sounds reasonable.
>
> I started looking through the code paths and I currently cannot
> see anything that would leave a message on a kernel rtnl socket.
>
> However I did a quick test adding a WARN_ON if there were any messages
> found in the queue during rtnl_unlock and I found this code path
> getting invoked from linkwatch_event. So there is clearly something I
> don't understand, and it sounds at odds just a bit from your
> description.
That sounds like a bug. Did you place the WARN_ON before or after
the mutex_unlock()?
next prev parent reply other threads:[~2007-09-30 15:39 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-29 1:00 [PATCH 1/5] net: Modify all rtnetlink methods to only work in the initial namespace Eric W. Biederman
2007-09-29 1:02 ` [PATCH 2/5] net: Make rtnetlink infrastructure network namespace aware Eric W. Biederman
[not found] ` <m1hcle9td8.fsf-T1Yj925okcoyDheHMi7gv2pdwda3JcWeAL8bYrjMMd8@public.gmane.org>
2007-09-29 1:04 ` [PATCH 3/5] net: Make the netlink methods in rtnetlink handle multiple network namespaces Eric W. Biederman
2007-09-29 1:07 ` [PATCH 4/5] net: Make AF_PACKET " Eric W. Biederman
2007-09-29 1:08 ` [PATCH 5/5] net: Make AF_UNIX per network namespace safe Eric W. Biederman
2007-09-29 15:47 ` Patrick McHardy
2007-09-29 17:03 ` Eric W. Biederman
2007-09-29 17:50 ` Patrick McHardy
2007-09-29 15:44 ` [PATCH 2/5] net: Make rtnetlink infrastructure network namespace aware Patrick McHardy
2007-09-29 16:51 ` Eric W. Biederman
2007-09-29 17:48 ` Patrick McHardy
2007-09-29 21:00 ` Eric W. Biederman
2007-09-30 13:13 ` [Devel] " Denis V. Lunev
2007-09-30 15:39 ` Patrick McHardy [this message]
2007-10-01 8:26 ` Denis V. Lunev
2007-10-01 8:45 ` Eric W. Biederman
2007-10-10 12:35 ` [Devel] [PATCH 1/5] net: Modify all rtnetlink methods to only work in the initial namespace Denis V. Lunev
2007-10-10 14:05 ` Daniel Lezcano
2007-10-10 14:29 ` Denis V. Lunev
2007-10-10 19:37 ` Eric W. Biederman
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