cnic: Fix occasional NULL pointer dereference during reboot.

We register with bnx2x before we allocate ctx_tbl structure, so it is
possible for bnx2x to call cnic_ctl before the structure is allocated.
This can sometimes cause NULL pointer dereference of cp->ctx_tbl.  We
fix this by adding simple checking for valid state before proceeding.
The cnic_ctl call is RCU protected so we don't have to deal with race
conditions.

Because of the additional checking, we need to finish the shutdown
before clearing the CNIC_UP flag.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/net/ethernet/broadcom/cnic.c b/drivers/net/ethernet/broadcom/cnic.c
index 0e9be2ba924e..31b05ad325d0 100644
--- a/drivers/net/ethernet/broadcom/cnic.c
+++ b/drivers/net/ethernet/broadcom/cnic.c
@@ -291,6 +291,9 @@ static int cnic_get_l5_cid(struct cnic_local *cp, u32 cid, u32 *l5_cid)
 {
         u32 i;
 
+        if (!cp->ctx_tbl)
+                return -EINVAL;
+
         for (i = 0; i < cp->max_cid_space; i++) {
                 if (cp->ctx_tbl[i].cid == cid) {
                         *l5_cid = i;
@@ -3220,6 +3223,9 @@ static int cnic_ctl(void *data, struct cnic_ctl_info *info)
                 u32 l5_cid;
                 struct cnic_local *cp = dev->cnic_priv;
 
+                if (!test_bit(CNIC_F_CNIC_UP, &dev->flags))
+                        break;
+
                 if (cnic_get_l5_cid(cp, cid, &l5_cid) == 0) {
                         struct cnic_context *ctx = &cp->ctx_tbl[l5_cid];
 
@@ -4253,8 +4259,6 @@ static int cnic_cm_shutdown(struct cnic_dev *dev)
         struct cnic_local *cp = dev->cnic_priv;
         int i;
 
-        cp->stop_cm(dev);
-
         if (!cp->csk_tbl)
                 return 0;
 
@@ -5290,6 +5294,7 @@ static void cnic_stop_hw(struct cnic_dev *dev)
                         i++;
                 }
                 cnic_shutdown_rings(dev);
+                cp->stop_cm(dev);
                 clear_bit(CNIC_F_CNIC_UP, &dev->flags);
                 RCU_INIT_POINTER(cp->ulp_ops[CNIC_ULP_L4], NULL);
                 synchronize_rcu();