From: Daniel Lezcano Date: Tue, 30 Oct 2007 22:38:18 +0000 (-0700) Subject: [NET]: Fix free_netdev on register_netdev failure. X-Git-Tag: v2.6.24-rc2~69^2~9 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=93ee31f14f6f7b5b427c2fdc715d5571eb0be9e5;p=pandora-kernel.git [NET]: Fix free_netdev on register_netdev failure. Point 1: The unregistering of a network device schedule a netdev_run_todo. This function calls dev->destructor when it is set and the destructor calls free_netdev. Point 2: In the case of an initialization of a network device the usual code is: * alloc_netdev * register_netdev -> if this one fails, call free_netdev and exit with error. Point 3: In the register_netdevice function at the later state, when the device is at the registered state, a call to the netdevice_notifiers is made. If one of the notification falls into an error, a rollback to the registered state is done using unregister_netdevice. Conclusion: When a network device fails to register during initialization because one network subsystem returned an error during a notification call chain, the network device is freed twice because of fact 1 and fact 2. The second free_netdev will be done with an invalid pointer. Proposed solution: The following patch move all the code of unregister_netdevice *except* the call to net_set_todo, to a new function "rollback_registered". The following functions are changed in this way: * register_netdevice: calls rollback_registered when a notification fails * unregister_netdevice: calls rollback_register + net_set_todo, the call order to net_set_todo is changed because it is the latest now. Since it justs add an element to a list that should not break anything. Signed-off-by: Daniel Lezcano Signed-off-by: David S. Miller --- Reading git-diff-tree failed