[PATCH AUTOSEL for 4.9 068/100] bnxt_en: Fix NULL pointer dereference in reopen failure path

[alexander . levin]

From: Sankar Patchineelam <sankar.patchinee...@broadcom.com>

[ Upstream commit 2247925f0942dc4e7c09b1cde45ca18461d94c5f ]

Net device reset can fail when the h/w or f/w is in a bad state.
Subsequent netdevice open fails in bnxt_hwrm_stat_ctx_alloc().
The cleanup invokes bnxt_hwrm_resource_free() which inturn
calls bnxt_disable_int().  In this routine, the code segment

if (ring->fw_ring_id != INVALID_HW_RING_ID)
   BNXT_CP_DB(cpr->cp_doorbell, cpr->cp_raw_cons);

results in NULL pointer dereference as cpr->cp_doorbell is not yet
initialized, and fw_ring_id is zero.

The fix is to initialize cpr fw_ring_id to INVALID_HW_RING_ID before
bnxt_init_chip() is invoked.

Signed-off-by: Sankar Patchineelam <sankar.patchinee...@broadcom.com>
Signed-off-by: Michael Chan <michael.c...@broadcom.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c 
b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 5d2cf56aed0e..fffc8cafe4ba 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -2381,6 +2381,18 @@ static int bnxt_init_one_rx_ring(struct bnxt *bp, int 
ring_nr)
        return 0;
 }
 
+static void bnxt_init_cp_rings(struct bnxt *bp)
+{
+       int i;
+
+       for (i = 0; i < bp->cp_nr_rings; i++) {
+               struct bnxt_cp_ring_info *cpr = &bp->bnapi[i]->cp_ring;
+               struct bnxt_ring_struct *ring = &cpr->cp_ring_struct;
+
+               ring->fw_ring_id = INVALID_HW_RING_ID;
+       }
+}
+
 static int bnxt_init_rx_rings(struct bnxt *bp)
 {
        int i, rc = 0;
@@ -4700,6 +4712,7 @@ static int bnxt_shutdown_nic(struct bnxt *bp, bool 
irq_re_init)
 
 static int bnxt_init_nic(struct bnxt *bp, bool irq_re_init)
 {
+       bnxt_init_cp_rings(bp);
        bnxt_init_rx_rings(bp);
        bnxt_init_tx_rings(bp);
        bnxt_init_ring_grps(bp, irq_re_init);
-- 
2.11.0