[PATCH 3.7+stable] pm: fix wrong error-checking condition

[PATCH 3.7+stable] pm: fix wrong error-checking condition

[Guennadi Liakhovetski]

dev_pm_qos_add_request() can return 0, 1, or a negative error code,
therefore the correct error test is "if (error < 0)." Checking just for
non-zero return code leads to erroneous setting of the req->dev pointer
to NULL, which then leads to a repeated call to
dev_pm_qos_add_ancestor_request() in st1232_ts_irq_handler(). This in turn
leads to an Oops, when the I2C host adapter is unloaded and reloaded again
because of the inconsistent state of its QoS request list.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---

Hi Rafael, please push to 3.7 and to stable.

 drivers/base/power/qos.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 74a67e0..fbbd4ed 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -451,7 +451,7 @@ int dev_pm_qos_add_ancestor_request(struct device *dev,
 	if (ancestor)
 		error = dev_pm_qos_add_request(ancestor, req, value);
 
-	if (error)
+	if (error < 0)
 		req->dev = NULL;
 
 	return error;
-- 
1.7.2.5

Re: [PATCH 3.7+stable] pm: fix wrong error-checking condition

[Rafael J. Wysocki]

On Friday, November 23, 2012 04:02:56 PM Guennadi Liakhovetski wrote:
> dev_pm_qos_add_request() can return 0, 1, or a negative error code,
> therefore the correct error test is "if (error < 0)." Checking just for
> non-zero return code leads to erroneous setting of the req->dev pointer
> to NULL, which then leads to a repeated call to
> dev_pm_qos_add_ancestor_request() in st1232_ts_irq_handler(). This in turn
> leads to an Oops, when the I2C host adapter is unloaded and reloaded again
> because of the inconsistent state of its QoS request list.
> 
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> ---
> 
> Hi Rafael, please push to 3.7 and to stable.

I will, thanks for the fix!

Rafael


>  drivers/base/power/qos.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
> index 74a67e0..fbbd4ed 100644
> --- a/drivers/base/power/qos.c
> +++ b/drivers/base/power/qos.c
> @@ -451,7 +451,7 @@ int dev_pm_qos_add_ancestor_request(struct device *dev,
>  	if (ancestor)
>  		error = dev_pm_qos_add_request(ancestor, req, value);
>  
> -	if (error)
> +	if (error < 0)
>  		req->dev = NULL;
>  
>  	return error;
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.