[PATCH net v3 3/5] net: mana: Guard mana_remove against double invocation

[Erni Sri Satya Vennela <ernis@linux.microsoft.com>]

If PM resume fails (e.g., mana_attach() returns an error), mana_probe()
calls mana_remove(), which tears down the device and sets
gd->gdma_context = NULL and gd->driver_data = NULL.

However, a failed resume callback does not automatically unbind the
driver. When the device is eventually unbound, mana_remove() is invoked
a second time. Without a NULL check, it dereferences gc->dev with
gc == NULL, causing a kernel panic.

Add an early return if gdma_context or driver_data is NULL so the second
invocation is harmless. Move the dev = gc->dev assignment after the
guard so it cannot dereference NULL.

Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Signed-off-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com>
---
Changes in v3:
* Add this patch to the patchset
---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 468ed60a8a00..ce1b7ec46a27 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -3731,11 +3731,16 @@ void mana_remove(struct gdma_dev *gd, bool suspending)
 	struct gdma_context *gc = gd->gdma_context;
 	struct mana_context *ac = gd->driver_data;
 	struct mana_port_context *apc;
-	struct device *dev = gc->dev;
+	struct device *dev;
 	struct net_device *ndev;
 	int err;
 	int i;
 
+	if (!gc || !ac)
+		return;
+
+	dev = gc->dev;
+
 	disable_work_sync(&ac->link_change_work);
 	cancel_delayed_work_sync(&ac->gf_stats_work);
 
-- 
2.34.1