mwifiex: pcie: don't allow cmd buffer reuse after reset

In rogue cases (due to other bugs) it's possible we try to process an
old command response *after* resetting the device. This could trigger a
double-free (or the SKB can get reallocated elsewhere...causing other
memory corruptions) in mwifiex_pcie_process_cmd_complete().

For safety (and symmetry) let's always NULL out the command buffer as we
free it up. We're already doing this for the command response buffer.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index 21f2201..f54053e 100644 (file)
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -1043,12 +1043,14 @@ static int mwifiex_pcie_delete_cmdrsp_buf(struct mwifiex_adapter *adapter)
                mwifiex_unmap_pci_memory(adapter, card->cmdrsp_buf,
                                         PCI_DMA_FROMDEVICE);
                dev_kfree_skb_any(card->cmdrsp_buf);
+               card->cmdrsp_buf = NULL;
        }
 
        if (card && card->cmd_buf) {
                mwifiex_unmap_pci_memory(adapter, card->cmd_buf,
                                         PCI_DMA_TODEVICE);
                dev_kfree_skb_any(card->cmd_buf);
+               card->cmd_buf = NULL;
        }
        return 0;
 }
@@ -2934,7 +2936,6 @@ static void mwifiex_pcie_free_buffers(struct mwifiex_adapter *adapter)
        mwifiex_pcie_delete_evtbd_ring(adapter);
        mwifiex_pcie_delete_rxbd_ring(adapter);
        mwifiex_pcie_delete_txbd_ring(adapter);
-       card->cmdrsp_buf = NULL;
 }
 
 /*