From: Matt Johnston matt@codeconstruct.com.au
[ Upstream commit b389a902dd5be4ece505a2e0463b9b034de04bf5 ]
The unregister check could be incorrectly triggered if a netdev changes its type after register. That is possible for a tun device using TUNSETLINK ioctl, resulting in mctp unregister failing and the netdev unregister waiting forever.
This was encountered by https://github.com/openthread/openthread/issues/8523
Neither check at register or unregister is required. They were added in an attempt to track down mctp_ptr being set unexpectedly, which should not happen in normal operation.
Fixes: 7b1871af75f3 ("mctp: Warn if pointer is set for a wrong dev type") Signed-off-by: Matt Johnston matt@codeconstruct.com.au Link: https://lore.kernel.org/r/20221215054933.2403401-1-matt@codeconstruct.com.au Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/mctp/device.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/net/mctp/device.c b/net/mctp/device.c index 99a3bda8852f..acb97b257428 100644 --- a/net/mctp/device.c +++ b/net/mctp/device.c @@ -429,12 +429,6 @@ static void mctp_unregister(struct net_device *dev) struct mctp_dev *mdev;
mdev = mctp_dev_get_rtnl(dev); - if (mdev && !mctp_known(dev)) { - // Sanity check, should match what was set in mctp_register - netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d", - __func__, dev->type); - return; - } if (!mdev) return;
@@ -451,14 +445,8 @@ static int mctp_register(struct net_device *dev) struct mctp_dev *mdev;
/* Already registered? */ - mdev = rtnl_dereference(dev->mctp_ptr); - - if (mdev) { - if (!mctp_known(dev)) - netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d", - __func__, dev->type); + if (rtnl_dereference(dev->mctp_ptr)) return 0; - }
/* only register specific types */ if (!mctp_known(dev))