[PATCH] hid: logitech: don't use stack based dj_report structures

[PATCH] hid: logitech: don't use stack based dj_report structures

[Marc Dionne]

On a system with a logitech wireless keyboard/mouse and DMA-API debugging
enabled, this warning appears at boot:

kernel: WARNING: at lib/dma-debug.c:929 check_for_stack.part.12+0x70/0xa7()
kernel: Hardware name: MS-7593
kernel: uhci_hcd 0000:00:1d.1: DMA-API: device driver maps memory fromstack [addr=ffff8801b0079c29]

Make logi_dj_recv_query_paired_devices and logi_dj_recv_switch_to_dj_mode
use a structure allocated with kzalloc rather than a stack based one.

Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
---
 drivers/hid/hid-logitech-dj.c |   38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 5e8a7ed..0f9c146 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -436,27 +436,37 @@ static int logi_dj_recv_send_report(struct dj_receiver_dev *djrcv_dev,
 
 static int logi_dj_recv_query_paired_devices(struct dj_receiver_dev *djrcv_dev)
 {
-	struct dj_report dj_report;
+	struct dj_report *dj_report;
+	int retval;
 
-	memset(&dj_report, 0, sizeof(dj_report));
-	dj_report.report_id = REPORT_ID_DJ_SHORT;
-	dj_report.device_index = 0xFF;
-	dj_report.report_type = REPORT_TYPE_CMD_GET_PAIRED_DEVICES;
-	return logi_dj_recv_send_report(djrcv_dev, &dj_report);
+	dj_report = kzalloc(sizeof(dj_report), GFP_KERNEL);
+	if (!dj_report)
+		return -ENOMEM;
+	dj_report->report_id = REPORT_ID_DJ_SHORT;
+	dj_report->device_index = 0xFF;
+	dj_report->report_type = REPORT_TYPE_CMD_GET_PAIRED_DEVICES;
+	retval = logi_dj_recv_send_report(djrcv_dev, dj_report);
+	kfree(dj_report);
+	return retval;
 }
 
 static int logi_dj_recv_switch_to_dj_mode(struct dj_receiver_dev *djrcv_dev,
 					  unsigned timeout)
 {
-	struct dj_report dj_report;
+	struct dj_report *dj_report;
+	int retval;
 
-	memset(&dj_report, 0, sizeof(dj_report));
-	dj_report.report_id = REPORT_ID_DJ_SHORT;
-	dj_report.device_index = 0xFF;
-	dj_report.report_type = REPORT_TYPE_CMD_SWITCH;
-	dj_report.report_params[CMD_SWITCH_PARAM_DEVBITFIELD] = 0x3F;
-	dj_report.report_params[CMD_SWITCH_PARAM_TIMEOUT_SECONDS] = (u8)timeout;
-	return logi_dj_recv_send_report(djrcv_dev, &dj_report);
+	dj_report = kzalloc(sizeof(dj_report), GFP_KERNEL);
+	if (!dj_report)
+		return -ENOMEM;
+	dj_report->report_id = REPORT_ID_DJ_SHORT;
+	dj_report->device_index = 0xFF;
+	dj_report->report_type = REPORT_TYPE_CMD_SWITCH;
+	dj_report->report_params[CMD_SWITCH_PARAM_DEVBITFIELD] = 0x3F;
+	dj_report->report_params[CMD_SWITCH_PARAM_TIMEOUT_SECONDS] = (u8)timeout;
+	retval = logi_dj_recv_send_report(djrcv_dev, dj_report);
+	kfree(dj_report);
+	return retval;
 }
 
 
-- 
1.7.10.2

Re: [PATCH] hid: logitech: don't use stack based dj_report structures

[Jiri Kosina]

On Fri, 1 Jun 2012, Marc Dionne wrote:

> On a system with a logitech wireless keyboard/mouse and DMA-API debugging
> enabled, this warning appears at boot:
> 
> kernel: WARNING: at lib/dma-debug.c:929 check_for_stack.part.12+0x70/0xa7()
> kernel: Hardware name: MS-7593
> kernel: uhci_hcd 0000:00:1d.1: DMA-API: device driver maps memory fromstack [addr=ffff8801b0079c29]
> 
> Make logi_dj_recv_query_paired_devices and logi_dj_recv_switch_to_dj_mode
> use a structure allocated with kzalloc rather than a stack based one.
> 
> Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

Applied, thanks Marc.

> ---
>  drivers/hid/hid-logitech-dj.c |   38 ++++++++++++++++++++++++--------------
>  1 file changed, 24 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
> index 5e8a7ed..0f9c146 100644
> --- a/drivers/hid/hid-logitech-dj.c
> +++ b/drivers/hid/hid-logitech-dj.c
> @@ -436,27 +436,37 @@ static int logi_dj_recv_send_report(struct dj_receiver_dev *djrcv_dev,
>  
>  static int logi_dj_recv_query_paired_devices(struct dj_receiver_dev *djrcv_dev)
>  {
> -	struct dj_report dj_report;
> +	struct dj_report *dj_report;
> +	int retval;
>  
> -	memset(&dj_report, 0, sizeof(dj_report));
> -	dj_report.report_id = REPORT_ID_DJ_SHORT;
> -	dj_report.device_index = 0xFF;
> -	dj_report.report_type = REPORT_TYPE_CMD_GET_PAIRED_DEVICES;
> -	return logi_dj_recv_send_report(djrcv_dev, &dj_report);
> +	dj_report = kzalloc(sizeof(dj_report), GFP_KERNEL);
> +	if (!dj_report)
> +		return -ENOMEM;
> +	dj_report->report_id = REPORT_ID_DJ_SHORT;
> +	dj_report->device_index = 0xFF;
> +	dj_report->report_type = REPORT_TYPE_CMD_GET_PAIRED_DEVICES;
> +	retval = logi_dj_recv_send_report(djrcv_dev, dj_report);
> +	kfree(dj_report);
> +	return retval;
>  }
>  
>  static int logi_dj_recv_switch_to_dj_mode(struct dj_receiver_dev *djrcv_dev,
>  					  unsigned timeout)
>  {
> -	struct dj_report dj_report;
> +	struct dj_report *dj_report;
> +	int retval;
>  
> -	memset(&dj_report, 0, sizeof(dj_report));
> -	dj_report.report_id = REPORT_ID_DJ_SHORT;
> -	dj_report.device_index = 0xFF;
> -	dj_report.report_type = REPORT_TYPE_CMD_SWITCH;
> -	dj_report.report_params[CMD_SWITCH_PARAM_DEVBITFIELD] = 0x3F;
> -	dj_report.report_params[CMD_SWITCH_PARAM_TIMEOUT_SECONDS] = (u8)timeout;
> -	return logi_dj_recv_send_report(djrcv_dev, &dj_report);
> +	dj_report = kzalloc(sizeof(dj_report), GFP_KERNEL);
> +	if (!dj_report)
> +		return -ENOMEM;
> +	dj_report->report_id = REPORT_ID_DJ_SHORT;
> +	dj_report->device_index = 0xFF;
> +	dj_report->report_type = REPORT_TYPE_CMD_SWITCH;
> +	dj_report->report_params[CMD_SWITCH_PARAM_DEVBITFIELD] = 0x3F;
> +	dj_report->report_params[CMD_SWITCH_PARAM_TIMEOUT_SECONDS] = (u8)timeout;
> +	retval = logi_dj_recv_send_report(djrcv_dev, dj_report);
> +	kfree(dj_report);
> +	return retval;
>  }
>  
>  
> -- 
> 1.7.10.2
> 

-- 
Jiri Kosina
SUSE Labs