2021-07-24 20:57:48

by Salah Triki

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Subject: [PATCH] tablet: acecad: update the reference count of the usb interface structure

Use usb_get_intf() and usb_put_intf() in order to update the reference
count of the usb interface structure.

Signed-off-by: Salah Triki <[email protected]>
---
drivers/input/tablet/acecad.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/input/tablet/acecad.c b/drivers/input/tablet/acecad.c
index a38d1fe97334..85fe134a30ee 100644
--- a/drivers/input/tablet/acecad.c
+++ b/drivers/input/tablet/acecad.c
@@ -151,7 +151,7 @@ static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_
goto fail2;
}

- acecad->intf = intf;
+ acecad->intf = usb_get_intf(intf);
acecad->input = input_dev;

if (dev->manufacturer)
@@ -236,6 +236,9 @@ static void usb_acecad_disconnect(struct usb_interface *intf)
input_unregister_device(acecad->input);
usb_free_urb(acecad->irq);
usb_free_coherent(udev, 8, acecad->data, acecad->data_dma);
+
+ usb_put_intf(acecad->intf);
+
kfree(acecad);
}

--
2.25.1


2021-07-27 12:40:59

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH] tablet: acecad: update the reference count of the usb interface structure

On Sat, Jul 24, 2021 at 09:55:42PM +0100, Salah Triki wrote:
> Use usb_get_intf() and usb_put_intf() in order to update the reference
> count of the usb interface structure.
>

This commit message doesn't say what the user visible effects are. If
you encountered this bug at runtime then please put the stack trace in
the commit mesage.

Add a Fixes tag.

> Signed-off-by: Salah Triki <[email protected]>
> ---
> drivers/input/tablet/acecad.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/input/tablet/acecad.c b/drivers/input/tablet/acecad.c
> index a38d1fe97334..85fe134a30ee 100644
> --- a/drivers/input/tablet/acecad.c
> +++ b/drivers/input/tablet/acecad.c
> @@ -151,7 +151,7 @@ static int usb_acecad_probe(struct usb_interface *intf, const struct usb_device_
> goto fail2;
> }
>
> - acecad->intf = intf;
> + acecad->intf = usb_get_intf(intf);
> acecad->input = input_dev;
>
> if (dev->manufacturer)

You need to call usb_put_intf() if input_register_device() fails.

regards,
dan carpenter


2021-07-29 00:55:45

by Salah Triki

[permalink] [raw]
Subject: Re: [PATCH] tablet: acecad: update the reference count of the usb interface structure

On Tue, Jul 27, 2021 at 03:37:56PM +0300, Dan Carpenter wrote:
> This commit message doesn't say what the user visible effects are. If
> you encountered this bug at runtime then please put the stack trace in
> the commit mesage.
>

I made this patch based on the following documentation of
usb_get_intf():

[quote]
Each live reference to a interface must be refcounted.

Drivers for USB interfaces should normally record such references
in their probe methods, when they bind to an interface, and release them
by calling usb_put_intf, in their disconnect methods.

[/quote]

Thanx

2021-07-29 08:33:57

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH] tablet: acecad: update the reference count of the usb interface structure

On Thu, Jul 29, 2021 at 01:54:27AM +0100, Salah Triki wrote:
> On Tue, Jul 27, 2021 at 03:37:56PM +0300, Dan Carpenter wrote:
> > This commit message doesn't say what the user visible effects are. If
> > you encountered this bug at runtime then please put the stack trace in
> > the commit mesage.
> >
>
> I made this patch based on the following documentation of
> usb_get_intf():
>
> [quote]
> Each live reference to a interface must be refcounted.
>
> Drivers for USB interfaces should normally record such references
> in their probe methods, when they bind to an interface, and release them
> by calling usb_put_intf, in their disconnect methods.
>
> [/quote]

Put that information in the commit message. Otherwise to review this
patch then I'm trying to look through the syzbot dashboard to find the
stack trace.

regards,
dan carpenter