[ldv-project] [PATCH] drivers: watchdog: rdc321x_wdt: Fix race condition bugs

Fri Aug 7 19:21:41 MSK 2020

On Fri, Aug 07, 2020 at 04:59:02PM +0530, madhuparnabhowmik10 at gmail.com wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik10 at gmail.com>
>> In rdc321x_wdt_probe(), rdc321x_wdt_device.queue is initialized
> after misc_register(), hence if ioctl is called before its
> initialization which can call rdc321x_wdt_start() function,
> it will see an uninitialized value of rdc321x_wdt_device.queue,
> hence initialize it before misc_register().
> Also, rdc321x_wdt_device.default_ticks is accessed in reset()
> function called from write callback, thus initialize it before
> misc_register().
>> Found by Linux Driver Verification project (linuxtesting.org).
>> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10 at gmail.com>

Reviewed-by: Guenter Roeck <linux at roeck-us.net>
Having said that ... this is yet another potentially obsolete driver.
You are really wasting your (and, fwiw, my) time.
Florian, any thoughts if support for this chip can/should be deprecated
or even removed ?
Guenter
> ---
> drivers/watchdog/rdc321x_wdt.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>> diff --git a/drivers/watchdog/rdc321x_wdt.c b/drivers/watchdog/rdc321x_wdt.c
> index 57187efeb86f..f0c94ea51c3e 100644
> --- a/drivers/watchdog/rdc321x_wdt.c
> +++ b/drivers/watchdog/rdc321x_wdt.c
> @@ -231,6 +231,8 @@ static int rdc321x_wdt_probe(struct platform_device *pdev)
>> 	rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
> 	rdc321x_wdt_device.base_reg = r->start;
> +	rdc321x_wdt_device.queue = 0;
> +	rdc321x_wdt_device.default_ticks = ticks;
>> 	err = misc_register(&rdc321x_wdt_misc);
> 	if (err < 0) {
> @@ -245,14 +247,11 @@ static int rdc321x_wdt_probe(struct platform_device *pdev)
> 				rdc321x_wdt_device.base_reg, RDC_WDT_RST);
>> 	init_completion(&rdc321x_wdt_device.stop);
> -	rdc321x_wdt_device.queue = 0;
>> 	clear_bit(0, &rdc321x_wdt_device.inuse);
>> 	timer_setup(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
>> -	rdc321x_wdt_device.default_ticks = ticks;
> -
> 	dev_info(&pdev->dev, "watchdog init success\n");
>> 	return 0;
> -- 
> 2.17.1
>