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From 37e3be495d8cf44f44890832e3a0fd12aa2aab88 Mon Sep 17 00:00:00 2001
From: Volodymyr Mytnyk <vmytnyk@marvell.com>
Date: Thu, 18 Nov 2021 21:51:40 +0200
Subject: [PATCH 4/7] net: marvell: prestera: fix double free issue on err path
Git-commit: e8d032507cb7912baf1d3e0af54516f823befefd
Patch-mainline: v5.16-rc3
References: git-fixes

fix error path handling in prestera_bridge_port_join() that
cases prestera driver to crash (see below).

 Trace:
   Internal error: Oops: 96000044 [#1] SMP
   Modules linked in: prestera_pci prestera uio_pdrv_genirq
   CPU: 1 PID: 881 Comm: ip Not tainted 5.15.0 #1
   pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
   pc : prestera_bridge_destroy+0x2c/0xb0 [prestera]
   lr : prestera_bridge_port_join+0x2cc/0x350 [prestera]
   sp : ffff800011a1b0f0
   ...
   x2 : ffff000109ca6c80 x1 : dead000000000100 x0 : dead000000000122
    Call trace:
   prestera_bridge_destroy+0x2c/0xb0 [prestera]
   prestera_bridge_port_join+0x2cc/0x350 [prestera]
   prestera_netdev_port_event.constprop.0+0x3c4/0x450 [prestera]
   prestera_netdev_event_handler+0xf4/0x110 [prestera]
   raw_notifier_call_chain+0x54/0x80
   call_netdevice_notifiers_info+0x54/0xa0
   __netdev_upper_dev_link+0x19c/0x380

Fixes: e1189d9a5fbe ("net: marvell: prestera: Add Switchdev driver implementation")
Signed-off-by: Volodymyr Mytnyk <vmytnyk@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/ethernet/marvell/prestera/prestera_switchdev.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
index 9a309169dbae..b3ff3d0987f8 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
@@ -496,8 +496,8 @@ int prestera_bridge_port_join(struct net_device *br_dev,
 
 	br_port = prestera_bridge_port_add(bridge, port->dev);
 	if (IS_ERR(br_port)) {
-		err = PTR_ERR(br_port);
-		goto err_brport_create;
+		prestera_bridge_put(bridge);
+		return PTR_ERR(br_port);
 	}
 
 	if (bridge->vlan_enabled)
@@ -511,8 +511,6 @@ int prestera_bridge_port_join(struct net_device *br_dev,
 
 err_port_join:
 	prestera_bridge_port_put(br_port);
-err_brport_create:
-	prestera_bridge_put(bridge);
 	return err;
 }
 
-- 
2.16.4