Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <4e61935b-b06b-1f2d-6c2b-79bdfd569cd6@roeck-us.net>
Date:   Thu, 27 Oct 2022 22:23:06 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.2.2
Subject: Re: [RFC][PATCH v2 20/31] timers: usb: Use del_timer_shutdown()
 before freeing timer
Content-Language: en-US
To:     Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Stephen Boyd <sboyd@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Felipe Balbi <balbi@kernel.org>,
        Johan Hovold <johan@kernel.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Mathias Nyman <mathias.nyman@linux.intel.com>,
        Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Matthias Kaehlcke <mka@chromium.org>,
        Michael Grzeschik <m.grzeschik@pengutronix.de>,
        Bhuvanesh Surachari <Bhuvanesh_Surachari@mentor.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        linux-usb@vger.kernel.org
References: <20221027150525.753064657@goodmis.org>
 <20221027150928.983388020@goodmis.org>
From:   Guenter Roeck <linux@roeck-us.net>
In-Reply-To: <20221027150928.983388020@goodmis.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 10/27/22 08:05, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> 
> Before a timer is freed, del_timer_shutdown() must be called.
> 
> Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home/
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Felipe Balbi <balbi@kernel.org>
> Cc: Johan Hovold <johan@kernel.org>
> Cc: Alan Stern <stern@rowland.harvard.edu>
> Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
> Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
> Cc: Matthias Kaehlcke <mka@chromium.org>
> Cc: Michael Grzeschik <m.grzeschik@pengutronix.de>
> Cc: Bhuvanesh Surachari <Bhuvanesh_Surachari@mentor.com>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: linux-usb@vger.kernel.org
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>   drivers/usb/core/hub.c              | 3 +++
>   drivers/usb/gadget/udc/m66592-udc.c | 2 +-
>   drivers/usb/serial/garmin_gps.c     | 2 +-
>   drivers/usb/serial/mos7840.c        | 2 +-
>   4 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index bbab424b0d55..397f263ab7da 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1261,6 +1261,9 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
>   
>   		/* Don't do a long sleep inside a workqueue routine */
>   		if (type == HUB_INIT2) {
> +			/* Timers must be shutdown before they are re-initialized */
> +			if (hub->init_work.work.func)
> +				del_timer_shutdown(&hub->init_work.timer);
>   			INIT_DELAYED_WORK(&hub->init_work, hub_init_func3);

A similar call to INIT_DELAYED_WORK() around line 1085 needs the same change.

It would be great if that can somehow be hidden in INIT_DELAYED_WORK().

Thanks,
Guenter

>   			queue_delayed_work(system_power_efficient_wq,
>   					&hub->init_work,
> diff --git a/drivers/usb/gadget/udc/m66592-udc.c b/drivers/usb/gadget/udc/m66592-udc.c
> index 931e6362a13d..a6e2f8358adf 100644
> --- a/drivers/usb/gadget/udc/m66592-udc.c
> +++ b/drivers/usb/gadget/udc/m66592-udc.c
> @@ -1519,7 +1519,7 @@ static int m66592_remove(struct platform_device *pdev)
>   
>   	usb_del_gadget_udc(&m66592->gadget);
>   
> -	del_timer_sync(&m66592->timer);
> +	del_timer_shutdown(&m66592->timer);
>   	iounmap(m66592->reg);
>   	free_irq(platform_get_irq(pdev, 0), m66592);
>   	m66592_free_request(&m66592->ep[0].ep, m66592->ep0_req);
> diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
> index f1a8d8343623..2a53f26468bd 100644
> --- a/drivers/usb/serial/garmin_gps.c
> +++ b/drivers/usb/serial/garmin_gps.c
> @@ -1405,7 +1405,7 @@ static void garmin_port_remove(struct usb_serial_port *port)
>   
>   	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
>   	usb_kill_urb(port->interrupt_in_urb);
> -	del_timer_sync(&garmin_data_p->timer);
> +	del_timer_shutdown(&garmin_data_p->timer);
>   	kfree(garmin_data_p);
>   }
>   
> diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
> index 6b12bb4648b8..a90a706d27de 100644
> --- a/drivers/usb/serial/mos7840.c
> +++ b/drivers/usb/serial/mos7840.c
> @@ -1726,7 +1726,7 @@ static void mos7840_port_remove(struct usb_serial_port *port)
>   		mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0300);
>   
>   		del_timer_sync(&mos7840_port->led_timer1);
> -		del_timer_sync(&mos7840_port->led_timer2);
> +		del_timer_shutdown(&mos7840_port->led_timer2);
>   
>   		usb_kill_urb(mos7840_port->led_urb);
>   		usb_free_urb(mos7840_port->led_urb);