target/linux/generic/patches-3.18/780-igb-Fix-Null-pointer-dereference-in-igb_reset_q_vect.patch

   1 From cb06d102327eadcd1bdc480bfd9f8876251d1007 Mon Sep 17 00:00:00 2001
   2 From: Christoph Paasch <christoph.paasch@uclouvain.be>
   3 Date: Fri, 21 Mar 2014 03:48:19 -0700
   4 Subject: [PATCH] igb: Fix Null-pointer dereference in igb_reset_q_vector
   5
   6 When igb_set_interrupt_capability() calls
   7 igb_reset_interrupt_capability() (e.g., because CONFIG_PCI_MSI is unset),
   8 num_q_vectors has been set but no vector has yet been allocated.
   9
  10 igb_reset_interrupt_capability() will then call igb_reset_q_vector,
  11 which assumes that the vector is allocated. As this is not the case, we
  12 are accessing a NULL-pointer.
  13
  14 This patch fixes it by checking that q_vector is indeed different from
  15 NULL.
  16
  17 Fixes: 02ef6e1d0b0023 (igb: Fix queue allocation method to accommodate changing during runtime)
  18 Cc: Carolyn Wyborny <carolyn.wyborny@intel.com>
  19 Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
  20 Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
  21 Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
  22 ---
  23  drivers/net/ethernet/intel/igb/igb_main.c | 6 ++++++
  24  1 file changed, 6 insertions(+)
  25
  26 --- a/drivers/net/ethernet/intel/igb/igb_main.c
  27 +++ b/drivers/net/ethernet/intel/igb/igb_main.c
  28 @@ -1034,6 +1034,12 @@ static void igb_reset_q_vector(struct ig
  29         if (!q_vector)
  30                 return;
  31
  32 +       /* Coming from igb_set_interrupt_capability, the vectors are not yet
  33 +        * allocated. So, q_vector is NULL so we should stop here.
  34 +        */
  35 +       if (!q_vector)
  36 +               return;
  37 +
  38         if (q_vector->tx.ring)
  39                 adapter->tx_ring[q_vector->tx.ring->queue_index] = NULL;
  40