igb: fix panic while dumping packets on Tx hang with IOMMU

This patch resolves a "BUG: unable to handle kernel paging request at ..."
oops while dumping packet data. The issue occurs with IOMMU enabled due to
the address provided by phys_to_virt().

This patch avoids phys_to_virt() by making using skb->data and the address
of the pages allocated for Rx.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index b7c2d5050572828c8d07e228b2e44235e9f01801..48cc4fb1a307f0d7c2821cc9f57c4c67d0ffc31b 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -462,10 +462,10 @@ static void igb_dump(struct igb_adapter *adapter)
                                (u64)buffer_info->time_stamp,
                                buffer_info->skb, next_desc);
 
-                       if (netif_msg_pktdata(adapter) && buffer_info->dma != 0)
+                       if (netif_msg_pktdata(adapter) && buffer_info->skb)
                                print_hex_dump(KERN_INFO, "",
                                        DUMP_PREFIX_ADDRESS,
-                                       16, 1, phys_to_virt(buffer_info->dma),
+                                       16, 1, buffer_info->skb->data,
                                        buffer_info->length, true);
                }
        }
@@ -547,18 +547,17 @@ rx_ring_summary:
                                        (u64)buffer_info->dma,
                                        buffer_info->skb, next_desc);
 
-                               if (netif_msg_pktdata(adapter)) {
+                               if (netif_msg_pktdata(adapter) &&
+                                   buffer_info->dma && buffer_info->skb) {
                                        print_hex_dump(KERN_INFO, "",
-                                               DUMP_PREFIX_ADDRESS,
-                                               16, 1,
-                                               phys_to_virt(buffer_info->dma),
-                                               IGB_RX_HDR_LEN, true);
+                                                 DUMP_PREFIX_ADDRESS,
+                                                 16, 1, buffer_info->skb->data,
+                                                 IGB_RX_HDR_LEN, true);
                                        print_hex_dump(KERN_INFO, "",
                                          DUMP_PREFIX_ADDRESS,
                                          16, 1,
-                                         phys_to_virt(
-                                           buffer_info->page_dma +
-                                           buffer_info->page_offset),
+                                         page_address(buffer_info->page) +
+                                                     buffer_info->page_offset,
                                          PAGE_SIZE/2, true);
                                }
                        }