On Wed, Jun 11, 2025 at 01:46:13AM -0700, Erni Sri Satya Vennela wrote:
> When net_shaper_ops are enabled for MANA, netdev_ops_lock
> becomes active.
>
> The netvsc sets up MANA VF via following call chain:
>
> netvsc_vf_setup()
> dev_change_flags()
> ...
> __dev_open() OR __dev_close()
>
> dev_change_flags() holds the netdev mutex via netdev_lock_ops.
>
> During this process, mana_create_txq() and mana_create_rxq()
> invoke netif_napi_add_tx(), netif_napi_add_weight(), and napi_enable(),
> all of which attempt to acquire the same lock,
> leading to a potential deadlock.
commit message could be better oriented.
>
> Similarly, mana_destroy_txq() and mana_destroy_rxq() call
> netif_napi_disable() and netif_napi_del(), which also contend
> for the same lock.
>
> Switch to the _locked variants of these APIs to avoid deadlocks
> when the netdev_ops_lock is held.
>
> Fixes: d4c22ec680c8 ("net: hold netdev instance lock during
> ndo_open/ndo_stop")
> Signed-off-by: Erni Sri Satya Vennela <er...@linux.microsoft.com>
> Reviewed-by: Haiyang Zhang <haiya...@microsoft.com>
> Reviewed-by: Shradha Gupta <shradhagu...@linux.microsoft.com>
> ---
> drivers/net/ethernet/microsoft/mana/mana_en.c | 39 ++++++++++++++-----
> 1 file changed, 30 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c
> b/drivers/net/ethernet/microsoft/mana/mana_en.c
> index ccd2885c939e..3c879d8a39e3 100644
> --- a/drivers/net/ethernet/microsoft/mana/mana_en.c
> +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
> @@ -1911,8 +1911,13 @@ static void mana_destroy_txq(struct mana_port_context
> *apc)
> napi = &apc->tx_qp[i].tx_cq.napi;
> if (apc->tx_qp[i].txq.napi_initialized) {
> napi_synchronize(napi);
> - napi_disable(napi);
> - netif_napi_del(napi);
> + if (netdev_need_ops_lock(napi->dev)) {
> + napi_disable_locked(napi);
> + netif_napi_del_locked(napi);
> + } else {
> + napi_disable(napi);
> + netif_napi_del(napi);
> + }
Instead of using if-else, we can used netdev_lock_ops(), followed by *_locked
api-s.
Same for rest of the patch.
Reviewed-by: Saurabh Sengar <ssen...@linux.microsoft.com>
- Saurabh
