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authorPavel Emelyanov <xemul@openvz.org>2008-05-02 20:49:39 -0400
committerJeff Garzik <jgarzik@redhat.com>2008-05-06 12:01:30 -0400
commitae68c39819ddf30549652962768a50edae5eec6f (patch)
tree0d0ef28152945ad23b72f6cff62a8dfc0345224b /drivers/net/bonding/bond_main.c
parentc4ebc66a1a8e3576322a9f47f0d06ec3c96a08d7 (diff)
bonding: Deadlock between bonding_store_bonds and bond_destroy_sysfs.
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> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers/net/bonding/bond_main.c')
-rw-r--r--drivers/net/bonding/bond_main.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 5509732d3f9d..e41b3e57260c 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4992,9 +4992,10 @@ err:
4992 destroy_workqueue(bond->wq); 4992 destroy_workqueue(bond->wq);
4993 } 4993 }
4994 4994
4995 bond_destroy_sysfs();
4996
4995 rtnl_lock(); 4997 rtnl_lock();
4996 bond_free_all(); 4998 bond_free_all();
4997 bond_destroy_sysfs();
4998 rtnl_unlock(); 4999 rtnl_unlock();
4999out: 5000out:
5000 return res; 5001 return res;
@@ -5006,9 +5007,10 @@ static void __exit bonding_exit(void)
5006 unregister_netdevice_notifier(&bond_netdev_notifier); 5007 unregister_netdevice_notifier(&bond_netdev_notifier);
5007 unregister_inetaddr_notifier(&bond_inetaddr_notifier); 5008 unregister_inetaddr_notifier(&bond_inetaddr_notifier);
5008 5009
5010 bond_destroy_sysfs();
5011
5009 rtnl_lock(); 5012 rtnl_lock();
5010 bond_free_all(); 5013 bond_free_all();
5011 bond_destroy_sysfs();
5012 rtnl_unlock(); 5014 rtnl_unlock();
5013} 5015}
5014 5016