Re: [PATCH 1/1] bnx2x: fix slowpath null crash

From: Zhu Yanjun <redacted>

When "NETDEV WATCHDOG: em4 (bnx2x): transmit queue 2 timed out" occurs,
BNX2X_SP_RTNL_TX_TIMEOUT is set. In the function bnx2x_sp_rtnl_task,
bnx2x_nic_unload and bnx2x_nic_load are executed to shutdown and open
NIC. In the function bnx2x_nic_load, bnx2x_alloc_mem allocates dma
failure. The message "bnx2x: [bnx2x_alloc_mem:8399(em4)]Can't
allocate memory" pops out. The variable slowpath is set to NULL.
When shutdown the NIC, the function bnx2x_nic_unload is called. In
the function bnx2x_nic_unload, the following functions are executed.
bnx2x_chip_cleanup
     bnx2x_set_storm_rx_mode
         bnx2x_set_q_rx_mode
             bnx2x_set_q_rx_mode
                 bnx2x_config_rx_mode
                     bnx2x_set_rx_mode_e2
In the function bnx2x_set_rx_mode_e2, the variable slowpath is operated.
Then the crash occurs.
To fix this crash, the variable slowpath is checked. And in the function
bnx2x_sp_rtnl_task, after dma memory allocation fails, another shutdown
and open NIC is executed.

CC: Joe Jin <redacted>
CC: Junxiao Bi <redacted>
Signed-off-by: Zhu Yanjun <redacted>
---
  drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 14 +++++++++++---
  1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
index c12b4d3..5929324 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c

@@ -9332,7 +9332,7 @@ void bnx2x_chip_cleanup(struct bnx2x *bp, int unload_mode, bool keep_link)
  	/* Schedule the rx_mode command */
  	if (test_bit(BNX2X_FILTER_RX_MODE_PENDING, &bp->sp_state))
  		set_bit(BNX2X_FILTER_RX_MODE_SCHED, &bp->sp_state);
-	else
+	else if (!bp->slowpath)
  		bnx2x_set_storm_rx_mode(bp);
  
  	/* Cleanup multicast configuration */

@@ -10271,8 +10271,16 @@ static void bnx2x_sp_rtnl_task(struct work_struct *work)
  		smp_mb();
  
  		bnx2x_nic_unload(bp, UNLOAD_NORMAL, true);
-		bnx2x_nic_load(bp, LOAD_NORMAL);
-
+		/*When ret value shows failure of allocation failure,
+		 *the nic is rebooted again. If open still fails, a error
+		 *message to notify the user.
+		 */
+		if (bnx2x_nic_load(bp, LOAD_NORMAL) == -ENOMEM) {
+			bnx2x_nic_unload(bp, UNLOAD_NORMAL, true);
+			if (bnx2x_nic_load(bp, LOAD_NORMAL)) {
+				BNX2X_ERR("Open the NIC fails again!\n");
+			}
+		}
  		rtnl_unlock();
  		return;
  	}