[PATCH] ipmi_ssif: fix unexpected driver unregister warning

[PATCH] ipmi_ssif: fix unexpected driver unregister warning

[Kefeng Wang]

If platform_driver_register() fails from init_ipmi_ssif(),
platform_driver_unregister() called unconditionally will
trigger following warning,

ipmi_ssif: Unable to register driver: -12
------------[ cut here ]------------
Unexpected driver unregister!
WARNING: CPU: 1 PID: 6305 at drivers/base/driver.c:193 driver_unregister+0x60/0x70 drivers/base/driver.c:193

Fix it by adding platform_registered variable, only unregister platform
driver when it is already successfully registered.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 drivers/char/ipmi/ipmi_ssif.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index cf8156d6bc07..305fa5054274 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -303,6 +303,7 @@ struct ssif_info {
 	((unsigned int) atomic_read(&(ssif)->stats[SSIF_STAT_ ## stat]))
 
 static bool initialized;
+static bool platform_registered;
 
 static void return_hosed_msg(struct ssif_info *ssif_info,
 			     struct ipmi_smi_msg *msg);
@@ -2088,6 +2089,8 @@ static int init_ipmi_ssif(void)
 		rv = platform_driver_register(&ipmi_driver);
 		if (rv)
 			pr_err("Unable to register driver: %d\n", rv);
+		else
+			platform_registered = true;
 	}
 
 	ssif_i2c_driver.address_list = ssif_address_list();
@@ -2111,7 +2114,7 @@ static void cleanup_ipmi_ssif(void)
 
 	kfree(ssif_i2c_driver.address_list);
 
-	if (ssif_trydmi)
+	if (ssif_trydmi && platform_registered)
 		platform_driver_unregister(&ipmi_driver);
 
 	free_ssif_clients();
-- 
2.20.1

Re: [PATCH] ipmi_ssif: fix unexpected driver unregister warning

[Corey Minyard]

On Fri, May 24, 2019 at 10:37:24PM +0800, Kefeng Wang wrote:
> If platform_driver_register() fails from init_ipmi_ssif(),
> platform_driver_unregister() called unconditionally will
> trigger following warning,

Yep, same as the ipmi_si change before.  Thanks, it's in my
next tree queued for the next cycle.

-corey

> 
> ipmi_ssif: Unable to register driver: -12
> ------------[ cut here ]------------
> Unexpected driver unregister!
> WARNING: CPU: 1 PID: 6305 at drivers/base/driver.c:193 driver_unregister+0x60/0x70 drivers/base/driver.c:193
> 
> Fix it by adding platform_registered variable, only unregister platform
> driver when it is already successfully registered.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>  drivers/char/ipmi/ipmi_ssif.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
> index cf8156d6bc07..305fa5054274 100644
> --- a/drivers/char/ipmi/ipmi_ssif.c
> +++ b/drivers/char/ipmi/ipmi_ssif.c
> @@ -303,6 +303,7 @@ struct ssif_info {
>  	((unsigned int) atomic_read(&(ssif)->stats[SSIF_STAT_ ## stat]))
>  
>  static bool initialized;
> +static bool platform_registered;
>  
>  static void return_hosed_msg(struct ssif_info *ssif_info,
>  			     struct ipmi_smi_msg *msg);
> @@ -2088,6 +2089,8 @@ static int init_ipmi_ssif(void)
>  		rv = platform_driver_register(&ipmi_driver);
>  		if (rv)
>  			pr_err("Unable to register driver: %d\n", rv);
> +		else
> +			platform_registered = true;
>  	}
>  
>  	ssif_i2c_driver.address_list = ssif_address_list();
> @@ -2111,7 +2114,7 @@ static void cleanup_ipmi_ssif(void)
>  
>  	kfree(ssif_i2c_driver.address_list);
>  
> -	if (ssif_trydmi)
> +	if (ssif_trydmi && platform_registered)
>  		platform_driver_unregister(&ipmi_driver);
>  
>  	free_ssif_clients();
> -- 
> 2.20.1
>