From: David Miller <davem@davemloft.net>
To: fubar@us.ibm.com
Cc: netdev@vger.kernel.org, jgarzik@pobox.com, xemul@openvz.org
Subject: Re: [PATCH 3/4] bonding: Deadlock between bonding_store_bonds and bond_destroy_sysfs.
Date: Fri, 02 May 2008 17:51:53 -0700 (PDT) [thread overview]
Message-ID: <20080502.175153.47024492.davem@davemloft.net> (raw)
In-Reply-To: <12097757842821-git-send-email-fubar@us.ibm.com>
From: Jay Vosburgh <fubar@us.ibm.com>
Date: Fri, 2 May 2008 17:49:39 -0700
> From: Pavel Emelyanov <xemul@openvz.org>
>
> The sysfs layer has an internal protection, that ensures, that
> all the process sitting inside ->sore/->show callback exits
> before the appropriate entry is unregistered (the calltraces
> are rather big, but I can provide them if required).
>
> On the other hand, bonding takes rtnl_lock in
> a) the bonding_store_bonds, i.e. in ->store callback,
> b) module exit before calling the sysfs unregister routines.
>
> Thus, the classical AB-BA deadlock may occur. To reproduce run
> # while :; do modprobe bonding; rmmod bonding; done
> and
> # while :; do echo '+bond%d' > /sys/class/net/bonding_masters ; done
> in parallel.
>
> The fix is to move the bond_destroy_sysfs out of the rtnl_lock,
> but _before_ bond_free_all to make sure no bonding devices exist
> after module unload.
>
> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
> Acked-by: Jay Vosburgh <fubar@us.ibm.com>
Acked-by: David S. Miller <davem@davemloft.net>
next prev parent reply other threads:[~2008-05-03 0:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-03 0:49 [PATCH 0/4] bonding: bug fixes for 2.6.26 Jay Vosburgh
2008-05-03 0:49 ` [PATCH 1/4] bonding: Do not call free_netdev for already registered device Jay Vosburgh
2008-05-03 0:49 ` [PATCH 2/4] bonding: fix error unwind in bonding_store_bonds Jay Vosburgh
2008-05-03 0:49 ` [PATCH 3/4] bonding: Deadlock between bonding_store_bonds and bond_destroy_sysfs Jay Vosburgh
2008-05-03 0:49 ` [PATCH 4/4] bonding: fix enslavement error unwinds Jay Vosburgh
2008-05-03 0:52 ` David Miller
2008-05-03 1:06 ` [PATCH REPOST " Jay Vosburgh
2008-05-03 1:07 ` David Miller
2008-05-03 0:51 ` David Miller [this message]
2008-05-03 0:51 ` [PATCH 2/4] bonding: fix error unwind in bonding_store_bonds David Miller
2008-05-03 0:51 ` [PATCH 1/4] bonding: Do not call free_netdev for already registered device David Miller
2008-05-06 16:17 ` Jeff Garzik
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