[PATCH net] net: wangxun: fix kernel panic due to null pointer

[PATCH net] net: wangxun: fix kernel panic due to null pointer

[Jiawen Wu]

When the device uses a custom subsystem vendor ID, the function
wx_sw_init() returns before the memory of 'wx->mac_table' is allocated.
The null pointer will causes the kernel panic.

Fixes: 79625f45ca73 ("net: wangxun: Move MAC address handling to libwx")
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
---
 drivers/net/ethernet/wangxun/libwx/wx_hw.c      | 8 +++++---
 drivers/net/ethernet/wangxun/ngbe/ngbe_main.c   | 4 +---
 drivers/net/ethernet/wangxun/txgbe/txgbe_main.c | 4 +---
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/wangxun/libwx/wx_hw.c b/drivers/net/ethernet/wangxun/libwx/wx_hw.c
index a3c5de9d547a..533e912af089 100644
--- a/drivers/net/ethernet/wangxun/libwx/wx_hw.c
+++ b/drivers/net/ethernet/wangxun/libwx/wx_hw.c
@@ -1769,10 +1769,12 @@ int wx_sw_init(struct wx *wx)
 		wx->subsystem_device_id = pdev->subsystem_device;
 	} else {
 		err = wx_flash_read_dword(wx, 0xfffdc, &ssid);
-		if (!err)
-			wx->subsystem_device_id = swab16((u16)ssid);
+		if (err < 0) {
+			wx_err(wx, "read of internal subsystem device id failed\n");
+			return err;
+		}
 
-		return err;
+		wx->subsystem_device_id = swab16((u16)ssid);
 	}
 
 	wx->mac_table = kcalloc(wx->mac.num_rar_entries,
diff --git a/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c b/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
index 3d43f808c86b..8db804543e66 100644
--- a/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
+++ b/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
@@ -121,10 +121,8 @@ static int ngbe_sw_init(struct wx *wx)
 
 	/* PCI config space info */
 	err = wx_sw_init(wx);
-	if (err < 0) {
-		wx_err(wx, "read of internal subsystem device id failed\n");
+	if (err < 0)
 		return err;
-	}
 
 	/* mac type, phy type , oem type */
 	ngbe_init_type_code(wx);
diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
index 70f0b5c01dac..526250102db2 100644
--- a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
+++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
@@ -364,10 +364,8 @@ static int txgbe_sw_init(struct wx *wx)
 
 	/* PCI config space info */
 	err = wx_sw_init(wx);
-	if (err < 0) {
-		wx_err(wx, "read of internal subsystem device id failed\n");
+	if (err < 0)
 		return err;
-	}
 
 	txgbe_init_type_code(wx);
 
-- 
2.27.0

Re: [PATCH net] net: wangxun: fix kernel panic due to null pointer

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-1

Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree.
Subject: [PATCH net] net: wangxun: fix kernel panic due to null pointer
Link: https://lore.kernel.org/stable/20231117101108.893335-1-jiawenwu%40trustnetic.com

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https://github.com/intel/lkp-tests/wiki

Re: [PATCH net] net: wangxun: fix kernel panic due to null pointer

[Simon Horman]

On Fri, Nov 17, 2023 at 06:11:08PM +0800, Jiawen Wu wrote:
> When the device uses a custom subsystem vendor ID, the function
> wx_sw_init() returns before the memory of 'wx->mac_table' is allocated.
> The null pointer will causes the kernel panic.
> 
> Fixes: 79625f45ca73 ("net: wangxun: Move MAC address handling to libwx")
> Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>

Thanks Jiawen Wu,

I agree with your analysis and that the problem was introduced by the cited
commit. The fix also looks good to me.

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net] net: wangxun: fix kernel panic due to null pointer

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Fri, 17 Nov 2023 18:11:08 +0800 you wrote:
> When the device uses a custom subsystem vendor ID, the function
> wx_sw_init() returns before the memory of 'wx->mac_table' is allocated.
> The null pointer will causes the kernel panic.
> 
> Fixes: 79625f45ca73 ("net: wangxun: Move MAC address handling to libwx")
> Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
> 
> [...]

Here is the summary with links:
  - [net] net: wangxun: fix kernel panic due to null pointer
    https://git.kernel.org/netdev/net/c/8ba2c459668c

You are awesome, thank you!
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