From: Niels Dossche dossche.niels@gmail.com
[ Upstream commit 46b348fd2d81a341b15fb3f3f986204b038f5c42 ]
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: 4a5fe57e7751 ("alx: use fine-grained locking instead of RTNL") Signed-off-by: Niels Dossche dossche.niels@gmail.com Link: https://lore.kernel.org/r/20220310232707.44251-1-dossche.niels@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/atheros/alx/main.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c index 4ad3fc72e74e..a89b93cb4e26 100644 --- a/drivers/net/ethernet/atheros/alx/main.c +++ b/drivers/net/ethernet/atheros/alx/main.c @@ -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; }