From: Thomas Graf <tgraf@suug.ch>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Berg <johannes@sipsolutions.net>,
Miles Lane <miles.lane@gmail.com>,
netdev@vger.kernel.org,
ALSA development <alsa-devel@alsa-project.org>,
YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Subject: Re: 2.6.25-rc8-mm1 -- INFO: possible circular locking dependency detected (while using iw to debug a wireless issue)
Date: Fri, 4 Apr 2008 21:53:23 +0200 [thread overview]
Message-ID: <20080404195323.GF20815@postel.suug.ch> (raw)
In-Reply-To: <20080404121133.7b0983d8@extreme>
* Stephen Hemminger <shemminger@vyatta.com> 2008-04-04 12:11
> The changes in git-net don't look locking related. I suspect either:
> wireless is calling netlink without holding rtnl_lock;
> or more likely conditional locking ctrl_dumpfamily is confusing lockdep.
>
> ctrl_dumpfamily only acquires genl_lock if one of the incoming parameters (chains_to_skip)
> is non-zero. Not sure what the design reason is, Thomas could you add a comment?
First call to ctrl_dumpfamily() is coming directly from the message
processing context where genl_lock is already held. Subsequence calls
come from netlink_recvmsg() so we have to take the lock separately.
However, I just noticed the condition should really be
chains_to_skip != 0 || fams_to_skip != 0
prev parent reply other threads:[~2008-04-04 19:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <a44ae5cd0804030741jc9c7aebx21a7635e827b190f@mail.gmail.com>
[not found] ` <a44ae5cd0804030741jc9c7aebx21a7635e827b190f-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-04-04 15:45 ` 2.6.25-rc8-mm1 -- INFO: possible circular locking dependency detected (while using iw to debug a wireless issue) Johannes Berg
2008-04-04 17:43 ` Andrew Morton
2008-04-04 19:11 ` Stephen Hemminger
2008-04-04 19:53 ` Thomas Graf [this message]
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