From: Arthur Kiyanovski akiyano@amazon.com
[ Upstream commit ce1f352162828ba07470328828a32f47aa759020 ]
Overview: We don't frequently change the msix vectors throughout the life cycle of the driver. We do so in two functions: ena_probe() and ena_restore(). ena_probe() is only called when the driver is loaded. ena_restore() on the other hand is called during device reset / resume operations.
We use num_io_queues for calculating and allocating the number of msix vectors. At ena_probe() this value is equal to max_num_io_queues and thus this is not an issue, however ena_restore() might be called after the number of io queues has changed.
A possible bug scenario is as follows:
* Change number of queues from 8 to 4. (num_io_queues = 4, max_num_io_queues = 8, msix_vecs = 9,) * Trigger reset occurs -> ena_restore is called. (num_io_queues = 4, max_num_io_queues =8 , msix_vecs = 5) * Change number of queues from 4 to 6. (num_io_queues = 6, max_num_io_queues = 8, msix_vecs = 5) * The driver will reset due to failure of check_for_rx_interrupt_queue()
Fix: This can be easily fixed by always using max_num_io_queues to init the msix_vecs, since this number won't change as opposed to num_io_queues.
Fixes: 4d19266022ec ("net: ena: multiple queue creation related cleanups") Signed-off-by: Sameeh Jubran sameehj@amazon.com Signed-off-by: Arthur Kiyanovski akiyano@amazon.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -1346,7 +1346,7 @@ static int ena_enable_msix(struct ena_ad }
/* Reserved the max msix vectors we might need */ - msix_vecs = ENA_MAX_MSIX_VEC(adapter->num_io_queues); + msix_vecs = ENA_MAX_MSIX_VEC(adapter->max_num_io_queues); netif_dbg(adapter, probe, adapter->netdev, "trying to enable MSI-X, vectors %d\n", msix_vecs);