| Message ID | 20221215054933.2403401-1-matt@codeconstruct.com.au (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | b389a902dd5be4ece505a2e0463b9b034de04bf5 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v2] mctp: Remove device type check at unregister | expand |
Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Thu, 15 Dec 2022 13:49:33 +0800 you wrote: > 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 > > [...] Here is the summary with links: - [net,v2] mctp: Remove device type check at unregister https://git.kernel.org/netdev/net/c/b389a902dd5b You are awesome, thank you!
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))
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> --- v2: Also remove the check from register net/mctp/device.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-)