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* [PATCH] usb: core: fix reference count leak in usb_port_resume
@ 2020-06-14  3:33 Aditya Pakki
  2020-06-14 13:42 ` Alan Stern
  0 siblings, 1 reply; 2+ messages in thread
From: Aditya Pakki @ 2020-06-14  3:33 UTC (permalink / raw)
  To: pakki001
  Cc: kjlu, wu000273, Greg Kroah-Hartman, Alan Stern, Eugeniu Rosca,
	Andrew Morton, Mathias Nyman, Kai-Heng Feng, Lee, Chiasheng,
	David Heinzelmann, Hardik Gajjar, linux-usb, linux-kernel

usb_port_resume() calls pm_runtime_get_sync() that increments
the reference counter. In case of failure, decrement the reference
count and return the error.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
---
 drivers/usb/core/hub.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b1e14beaac5f..a9231f27144e 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3542,6 +3542,7 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
 		if (status < 0) {
 			dev_dbg(&udev->dev, "can't resume usb port, status %d\n",
 					status);
+			pm_runtime_put_sync(&port_dev->dev);
 			return status;
 		}
 	}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] usb: core: fix reference count leak in usb_port_resume
  2020-06-14  3:33 [PATCH] usb: core: fix reference count leak in usb_port_resume Aditya Pakki
@ 2020-06-14 13:42 ` Alan Stern
  0 siblings, 0 replies; 2+ messages in thread
From: Alan Stern @ 2020-06-14 13:42 UTC (permalink / raw)
  To: Aditya Pakki
  Cc: kjlu, wu000273, Greg Kroah-Hartman, Eugeniu Rosca, Andrew Morton,
	Mathias Nyman, Kai-Heng Feng, Lee, Chiasheng, David Heinzelmann,
	Hardik Gajjar, linux-usb, linux-kernel

On Sat, Jun 13, 2020 at 10:33:53PM -0500, Aditya Pakki wrote:
> usb_port_resume() calls pm_runtime_get_sync() that increments
> the reference counter. In case of failure, decrement the reference
> count and return the error.
> 
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> ---
>  drivers/usb/core/hub.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index b1e14beaac5f..a9231f27144e 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -3542,6 +3542,7 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
>  		if (status < 0) {
>  			dev_dbg(&udev->dev, "can't resume usb port, status %d\n",
>  					status);
> +			pm_runtime_put_sync(&port_dev->dev);

This is wrong; you need to do test_and_clear_bit(port1, 
hub->child_usage_bits) before calling pm_runtime_put_sync().  Otherwise 
the child_usage_bits value will get out of sync with the port's runtime 
status.

Alan Stern


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2020-06-14  3:33 [PATCH] usb: core: fix reference count leak in usb_port_resume Aditya Pakki
2020-06-14 13:42 ` Alan Stern

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