Hello Horatiu Vultur,
The patch 2ea1cbac267e: "net: lan966x: Update FDMA to change MTU."
from Apr 8, 2022, leads to the following Smatch static checker
warning:
drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c:736 lan966x_fdma_reload()
warn: 'rx_dcbs' was already freed.
drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
685 static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
686 {
687 void *rx_dcbs, *tx_dcbs, *tx_dcbs_buf;
688 dma_addr_t rx_dma, tx_dma;
689 u32 size;
690 int err;
691
692 /* Store these for later to free them */
693 rx_dma = lan966x->rx.dma;
694 tx_dma = lan966x->tx.dma;
695 rx_dcbs = lan966x->rx.dcbs;
696 tx_dcbs = lan966x->tx.dcbs;
697 tx_dcbs_buf = lan966x->tx.dcbs_buf;
698
699 napi_synchronize(&lan966x->napi);
700 napi_disable(&lan966x->napi);
701 lan966x_fdma_stop_netdev(lan966x);
702
703 lan966x_fdma_rx_disable(&lan966x->rx);
704 lan966x_fdma_rx_free_pages(&lan966x->rx);
705 lan966x->rx.page_order = round_up(new_mtu, PAGE_SIZE) / PAGE_SIZE - 1;
706 err = lan966x_fdma_rx_alloc(&lan966x->rx);
707 if (err)
708 goto restore;
709 lan966x_fdma_rx_start(&lan966x->rx);
710
711 size = sizeof(struct lan966x_rx_dcb) * FDMA_DCB_MAX;
712 size = ALIGN(size, PAGE_SIZE);
713 dma_free_coherent(lan966x->dev, size, rx_dcbs, rx_dma);
^^^^^^^
Freed
714
715 lan966x_fdma_tx_disable(&lan966x->tx);
716 err = lan966x_fdma_tx_alloc(&lan966x->tx);
717 if (err)
718 goto restore_tx;
^^^^^^^^^^^^^^^
719
720 size = sizeof(struct lan966x_tx_dcb) * FDMA_DCB_MAX;
721 size = ALIGN(size, PAGE_SIZE);
722 dma_free_coherent(lan966x->dev, size, tx_dcbs, tx_dma);
723
724 kfree(tx_dcbs_buf);
725
726 lan966x_fdma_wakeup_netdev(lan966x);
727 napi_enable(&lan966x->napi);
728
729 return err;
730 restore:
731 lan966x->rx.dma = rx_dma;
732 lan966x->tx.dma = tx_dma;
733 lan966x_fdma_rx_start(&lan966x->rx);
734
735 restore_tx:
--> 736 lan966x->rx.dcbs = rx_dcbs;
^^^^^^^
737 lan966x->tx.dcbs = tx_dcbs;
738 lan966x->tx.dcbs_buf = tx_dcbs_buf;
739
740 return err;
741 }
regards,
dan carpenter
