RSS configuration requires a valid RX indirection table. When the device
reports a single receive queue, rndis_filter_device_add() does not
allocate an indirection table, accepting RSS hash key updates in this
state leads to a hang.

Fix this by gating netvsc_set_rxfh() on ndc->rx_table_sz and return
-EOPNOTSUPP when the table is absent. This aligns set_rxfh with the device
capabilities and prevents incorrect behavior.

Fixes: 962f3fee83a4 ("netvsc: add ethtool ops to get/set RSS key")
Signed-off-by: Aditya Garg <[email protected]>
Reviewed-by: Dipayaan Roy <[email protected]>
---
 drivers/net/hyperv/netvsc_drv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 3d47d749ef9f..cbd52cb79268 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1750,6 +1750,9 @@ static int netvsc_set_rxfh(struct net_device *dev,
            rxfh->hfunc != ETH_RSS_HASH_TOP)
                return -EOPNOTSUPP;
 
+       if (!ndc->rx_table_sz)
+               return -EOPNOTSUPP;
+
        rndis_dev = ndev->extension;
        if (rxfh->indir) {
                for (i = 0; i < ndc->rx_table_sz; i++)
-- 
2.43.0


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