[PATCH] net: ethernet: ti: cpsw: fix NULL pointer dereference in switch mode

[PATCH] net: ethernet: ti: cpsw: fix NULL pointer dereference in switch mode

[Grygorii Strashko]

In switch mode on struct cpsw_slave->ndev field will be initialized with
proper value only for the one cpsw slave port, as result
cpsw_get_usage_count() will generate "Unable to handle kernel NULL pointer
dereference" exception when first ethernet interface is opening
cpsw_ndo_open(). This issue causes boot regression on AM335x EVM and
reproducible on am57xx-evm (switch mode).
Fix it by adding additional check for !cpsw->slaves[i].ndev in
cpsw_get_usage_count().

Cc: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
fixes: 03fd01ad0eea ("net: ethernet: ti: cpsw: don't duplicate ndev_running")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
 drivers/net/ethernet/ti/cpsw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 67b7323..35a95dc 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -677,7 +677,7 @@ static int cpsw_get_usage_count(struct cpsw_common *cpsw)
 	u32 usage_count = 0;
 
 	for (i = 0; i < cpsw->data.slaves; i++)
-		if (netif_running(cpsw->slaves[i].ndev))
+		if (cpsw->slaves[i].ndev && netif_running(cpsw->slaves[i].ndev))
 			usage_count++;
 
 	return usage_count;
-- 
2.10.1.dirty

Re: [PATCH] net: ethernet: ti: cpsw: fix NULL pointer dereference in switch mode

[Ivan Khoronzhuk]

On Tue, Jan 31, 2017 at 02:04:04PM -0600, Grygorii Strashko wrote:
> In switch mode on struct cpsw_slave->ndev field will be initialized with
> proper value only for the one cpsw slave port, as result
> cpsw_get_usage_count() will generate "Unable to handle kernel NULL pointer
> dereference" exception when first ethernet interface is opening
> cpsw_ndo_open(). This issue causes boot regression on AM335x EVM and
> reproducible on am57xx-evm (switch mode).
> Fix it by adding additional check for !cpsw->slaves[i].ndev in
> cpsw_get_usage_count().
> 
> Cc: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
> fixes: 03fd01ad0eea ("net: ethernet: ti: cpsw: don't duplicate ndev_running")
> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
> ---

Yes, unfortunately forgot to add it. Thanks.
Reviewed-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>


>  drivers/net/ethernet/ti/cpsw.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
> index 67b7323..35a95dc 100644
> --- a/drivers/net/ethernet/ti/cpsw.c
> +++ b/drivers/net/ethernet/ti/cpsw.c
> @@ -677,7 +677,7 @@ static int cpsw_get_usage_count(struct cpsw_common *cpsw)
>  	u32 usage_count = 0;
>  
>  	for (i = 0; i < cpsw->data.slaves; i++)
> -		if (netif_running(cpsw->slaves[i].ndev))
> +		if (cpsw->slaves[i].ndev && netif_running(cpsw->slaves[i].ndev))
>  			usage_count++;
>  
>  	return usage_count;
> -- 
> 2.10.1.dirty
> 

Re: [PATCH] net: ethernet: ti: cpsw: fix NULL pointer dereference in switch mode

[David Miller]

From: Grygorii Strashko <grygorii.strashko@ti.com>
Date: Tue, 31 Jan 2017 14:04:04 -0600

> In switch mode on struct cpsw_slave->ndev field will be initialized with
> proper value only for the one cpsw slave port, as result
> cpsw_get_usage_count() will generate "Unable to handle kernel NULL pointer
> dereference" exception when first ethernet interface is opening
> cpsw_ndo_open(). This issue causes boot regression on AM335x EVM and
> reproducible on am57xx-evm (switch mode).
> Fix it by adding additional check for !cpsw->slaves[i].ndev in
> cpsw_get_usage_count().
> 
> Cc: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
> fixes: 03fd01ad0eea ("net: ethernet: ti: cpsw: don't duplicate ndev_running")

Please capitalize "Fixes: " in the future.

> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>

Applied, thanks.