[PATCH net] net: ngbe: fix NULL pointer dereference in non-MSI-X interrupt enabling

In non-MSI-X mode (such as legacy INTx or single MSI), wx->msix_entry is
not allocated or initialized. Calling NGBE_INTR_MISC(wx) dereferences
wx->msix_entry->entry, leading to a NULL pointer dereference crash.

This issue was introduced by fixing the IRQ vector when the number of
VFs is 7. Since macro NGBE_INTR_MISC is used in only one place and
relies on MSI-X allocation, remove it.

Fix the issue by explicitly checking WX_FLAG_IRQ_VECTOR_SHARED to
determine the correct vector index and using BIT() to convert it into
the interrupt mask required by wx_intr_enable().

Fixes: 4174c0c331a2 ("net: ngbe: specify IRQ vector when the number of VFs is 7")
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
---
 drivers/net/ethernet/wangxun/ngbe/ngbe_main.c | 4 +++-
 drivers/net/ethernet/wangxun/ngbe/ngbe_type.h | 1 -
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c b/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
index a16221995909..5d89fc84e8bc 100644
--- a/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
+++ b/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c

@@ -180,8 +180,10 @@ static void ngbe_irq_enable(struct wx *wx, bool queues)
 	/* mask interrupt */
 	if (queues)
 		wx_intr_enable(wx, NGBE_INTR_ALL);
+	else if (test_bit(WX_FLAG_IRQ_VECTOR_SHARED, wx->flags))
+		wx_intr_enable(wx, BIT(0));
 	else
-		wx_intr_enable(wx, NGBE_INTR_MISC(wx));
+		wx_intr_enable(wx, BIT(wx->num_q_vectors));
 }
 
 /**

diff --git a/drivers/net/ethernet/wangxun/ngbe/ngbe_type.h b/drivers/net/ethernet/wangxun/ngbe/ngbe_type.h
index 7077a0da4c98..a990a622f7b7 100644
--- a/drivers/net/ethernet/wangxun/ngbe/ngbe_type.h
+++ b/drivers/net/ethernet/wangxun/ngbe/ngbe_type.h

@@ -82,7 +82,6 @@
 #define NGBE_PX_MISC_IC_TIMESYNC		BIT(11) /* time sync */
 
 #define NGBE_INTR_ALL				0x1FF
-#define NGBE_INTR_MISC(A)			BIT((A)->msix_entry->entry)
 
 #define NGBE_PHY_CONFIG(reg_offset)		(0x14000 + ((reg_offset) * 4))
 #define NGBE_CFG_LAN_SPEED			0x14440

-- 
2.51.0