netdev - Re: [PATCH] netconsole: fix deadlock when removing net driver that netconsole is using (v2)

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Message-Id: <20110422.143408.112583207.davem@davemloft.net>
Date:	Fri, 22 Apr 2011 14:34:08 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	nhorman@...driver.com
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH] netconsole: fix deadlock when removing net driver that
 netconsole is using (v2)

From: Neil Horman <nhorman@...driver.com>
Date: Fri, 22 Apr 2011 17:31:45 -0400

> I understand what you're saying here, but I think we're ok in this particular
> case.  I say that because all other callers of __netpoll_cleanup, call it via
> netpoll_cleanup, which does the dev_put under protection of the rtnl_lock.  This
> call is also under the rtnl_lock protection, its just taken when the event
> notification is made (thats why we call __netpoll_cleanup instead of
> netpoll_cleanup).  The target_list_lock just protects the integrity of the
> netconsole_target list.  If someone disables a netconsole via configfs, they'll
> block on the rtnl_lock.  Since no path through configfs takes the
> target_list_lock and rtnl (via netpoll_cleanup) in any nested fashion, we're
> safe from deadlock.

That's right, rtnl saves us.

Thanks for explaining, applied, thanks!
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