The following commit has been merged in the linux branch: commit d9d5283228d0c752f199c901fff6e1405dc91bcb Author: Jiri Bohac jbohac@suse.cz Date: Wed Oct 28 22:23:54 2009 -0700
bonding: fix a race condition in calls to slave MII ioctls
In mii monitor mode, bond_check_dev_link() calls the the ioctl handler of slave devices. It stores the ndo_do_ioctl function pointer to a static (!) ioctl variable and later uses it to call the handler with the IOCTL macro.
If another thread executes bond_check_dev_link() at the same time (even with a different bond, which none of the locks prevent), a race condition occurs. If the two racing slaves have different drivers, this may result in one driver's ioctl handler being called with a pointer to a net_device controlled with a different driver, resulting in unpredictable breakage.
Unless I am overlooking something, the "static" must be a copy'n'paste error (?).
Signed-off-by: Jiri Bohac jbohac@suse.cz Signed-off-by: David S. Miller davem@davemloft.net
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 3f05267..40fb5ee 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -691,7 +691,7 @@ static int bond_check_dev_link(struct bonding *bond, struct net_device *slave_dev, int reporting) { const struct net_device_ops *slave_ops = slave_dev->netdev_ops; - static int (*ioctl)(struct net_device *, struct ifreq *, int); + int (*ioctl)(struct net_device *, struct ifreq *, int); struct ifreq ifr; struct mii_ioctl_data *mii;