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.

(backported from upstream commit a2028b2376a858cb68a7fcc129f6508f59b45381)
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Joe Jin <joe.jin@oracle.com>

diff --git a/drivers/net/cnic.c b/drivers/net/cnic.c
index 2d7660d8396bf3a775837b7fb795ca2c6af2135a..5d7129d049bd2b69d8b9ff0eb2df940f6391d8b2 100644 (file)
--- a/drivers/net/cnic.c
+++ b/drivers/net/cnic.c
@@ -286,6 +286,9 @@ 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;
@@ -3213,6 +3216,9 @@ 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];
 
@@ -4246,8 +4252,6 @@ 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;
 
@@ -5283,6 +5287,7 @@ 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_assign_pointer(cp->ulp_ops[CNIC_ULP_L4], NULL);
                synchronize_rcu();