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* [PATCH] USB: usb-skeleton.c: fix compilation error and restore kref_put on fail in skel_open
@ 2012-10-07  9:57 Constantine Shulyupin
  2012-10-10  9:55 ` Oliver Neukum
  0 siblings, 1 reply; 2+ messages in thread
From: Constantine Shulyupin @ 2012-10-07  9:57 UTC (permalink / raw)
  To: gregkh; +Cc: linux-usb, linux-kernel, Constantine Shulyupin

From: Constantine Shulyupin <const@MakeLinux.com>

Function skel_open increments usage count for the device with kref_get and the usage count should be decremented on the function failure.

Some last changes in function skel_open and finally commit
52a7499 Revert "USB: usb-skeleton.c: fix open/disconnect race"
introduced a bug in function skel_open, which this patch fixes.

Signed-off-by: Constantine Shulyupin <const@MakeLinux.com>
---
 drivers/usb/usb-skeleton.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 0616f23..027005b 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -113,8 +113,10 @@ static int skel_open(struct inode *inode, struct file *file)
 	mutex_lock(&dev->io_mutex);
 
 	retval = usb_autopm_get_interface(interface);
-	if (retval)
-		goto out_err;
+	if (retval) {
+		kref_put(&dev->kref, skel_delete);
+		goto exit;
+	}
 
 	/* save our object in the file's private structure */
 	file->private_data = dev;
-- 
1.7.9.5


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

* Re: [PATCH] USB: usb-skeleton.c: fix compilation error and restore kref_put on fail in skel_open
  2012-10-07  9:57 [PATCH] USB: usb-skeleton.c: fix compilation error and restore kref_put on fail in skel_open Constantine Shulyupin
@ 2012-10-10  9:55 ` Oliver Neukum
  0 siblings, 0 replies; 2+ messages in thread
From: Oliver Neukum @ 2012-10-10  9:55 UTC (permalink / raw)
  To: Constantine Shulyupin; +Cc: gregkh, linux-usb, linux-kernel

On Sunday 07 October 2012 11:57:12 Constantine Shulyupin wrote:
> From: Constantine Shulyupin <const@MakeLinux.com>
> 
> Function skel_open increments usage count for the device with kref_get and the usage count should be decremented on the function failure.
> 
> Some last changes in function skel_open and finally commit
> 52a7499 Revert "USB: usb-skeleton.c: fix open/disconnect race"
> introduced a bug in function skel_open, which this patch fixes.
> 
> Signed-off-by: Constantine Shulyupin <const@MakeLinux.com>
> ---
>  drivers/usb/usb-skeleton.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
> index 0616f23..027005b 100644
> --- a/drivers/usb/usb-skeleton.c
> +++ b/drivers/usb/usb-skeleton.c
> @@ -113,8 +113,10 @@ static int skel_open(struct inode *inode, struct file *file)
>  	mutex_lock(&dev->io_mutex);
>  
>  	retval = usb_autopm_get_interface(interface);
> -	if (retval)
> -		goto out_err;
> +	if (retval) {
> +		kref_put(&dev->kref, skel_delete);
> +		goto exit;
> +	}
>  
>  	/* save our object in the file's private structure */
>  	file->private_data = dev;

Hi,

good catch, but the fix is wrong. You also need to drop the lock.

	Regards
		Oliver



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

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2012-10-07  9:57 [PATCH] USB: usb-skeleton.c: fix compilation error and restore kref_put on fail in skel_open Constantine Shulyupin
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