forked from Minki/linux
Staging: batman-adv: Don't use net_dev after dev_put
dev_put allows a device to be freed when all its references are dropped. After that we are not allowed to access that information anymore. Access to the data structure of a net_device must be surrounded a dev_hold and ended using dev_put. batman-adv adds a device to its own management structure in hardif_add_interface and will release it in hardif_remove_interface. Thus it must hold a reference all the time between those functions to prevent any access to the already released net_device structure. Reported-by: Tim Glaremin <Tim.Glaremin@web.de> Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -194,8 +194,6 @@ static void hardif_activate_interface(struct net_device *net_dev,
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if (batman_if->if_status != IF_INACTIVE)
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return;
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dev_hold(batman_if->net_dev);
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update_mac_addresses(batman_if);
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batman_if->if_status = IF_TO_BE_ACTIVATED;
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@ -222,8 +220,6 @@ static void hardif_deactivate_interface(struct net_device *net_dev,
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(batman_if->if_status != IF_TO_BE_ACTIVATED))
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return;
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dev_put(batman_if->net_dev);
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batman_if->if_status = IF_INACTIVE;
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bat_info(net_dev, "Interface deactivated: %s\n", batman_if->dev);
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@ -318,11 +314,13 @@ static struct batman_if *hardif_add_interface(struct net_device *net_dev)
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if (ret != 1)
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goto out;
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dev_hold(net_dev);
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batman_if = kmalloc(sizeof(struct batman_if), GFP_ATOMIC);
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if (!batman_if) {
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pr_err("Can't add interface (%s): out of memory\n",
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net_dev->name);
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goto out;
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goto release_dev;
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}
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batman_if->dev = kstrdup(net_dev->name, GFP_ATOMIC);
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@ -346,6 +344,8 @@ free_dev:
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kfree(batman_if->dev);
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free_if:
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kfree(batman_if);
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release_dev:
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dev_put(net_dev);
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out:
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return NULL;
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}
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@ -374,6 +374,7 @@ static void hardif_remove_interface(struct batman_if *batman_if)
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batman_if->if_status = IF_TO_BE_REMOVED;
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list_del_rcu(&batman_if->list);
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sysfs_del_hardif(&batman_if->hardif_obj);
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dev_put(batman_if->net_dev);
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call_rcu(&batman_if->rcu, hardif_free_interface);
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}
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