Commit 46b348fd authored by Niels Dossche's avatar Niels Dossche Committed by Jakub Kicinski
Browse files

alx: acquire mutex for alx_reinit in alx_change_mtu 



alx_reinit has a lockdep assertion that the alx->mtx mutex must be held.
alx_reinit is called from two places: alx_reset and alx_change_mtu.
alx_reset does acquire alx->mtx before calling alx_reinit.
alx_change_mtu does not acquire this mutex, nor do its callers or any
path towards alx_change_mtu.
Acquire the mutex in alx_change_mtu.

The issue was introduced when the fine-grained locking was introduced
to the code to replace the RTNL. The same commit also introduced the
lockdep assertion.

Fixes: 4a5fe57e ("alx: use fine-grained locking instead of RTNL")
Signed-off-by: default avatarNiels Dossche <dossche.niels@gmail.com>
Link: https://lore.kernel.org/r/20220310232707.44251-1-dossche.niels@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5e34af41

drivers/net/ethernet/atheros/alx/main.c

+4 −1
Original line number Diff line number Diff line
@@ -1181,8 +1181,11 @@ static int alx_change_mtu(struct net_device *netdev, int mtu) 
	alx->hw.mtu = mtu;

	alx->rxbuf_size = max(max_frame, ALX_DEF_RXBUF_SIZE);

	netdev_update_features(netdev);

	if (netif_running(netdev))

	if (netif_running(netdev)) {

		mutex_lock(&alx->mtx);

		alx_reinit(alx);

		mutex_unlock(&alx->mtx);

	}

	return 0;

}