On Wed, May 12, 2021 at 02:57:56PM +0800, Zou Wei wrote:
> This driver's remove path calls del_timer(). However, that function
> does not wait until the timer handler finishes. This means that the
> timer handler may still be running after the driver's remove function
> has finished, which would result in a use-after-free.
>
> Fix by calling del_timer_sync(), which makes sure the timer handler
> has finished, and unable to re-schedule itself.
>
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Zou Wei <zou_wei@xxxxxxxxxx>
If you have more of those, _please_ submit them together to save review time.
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Guenter
> ---
> drivers/watchdog/lpc18xx_wdt.c | 2 +-
> drivers/watchdog/w83877f_wdt.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c
> index 78cf11c..60b6d74 100644
> --- a/drivers/watchdog/lpc18xx_wdt.c
> +++ b/drivers/watchdog/lpc18xx_wdt.c
> @@ -292,7 +292,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev)
> struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);
>
> dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n");
> - del_timer(&lpc18xx_wdt->timer);
> + del_timer_sync(&lpc18xx_wdt->timer);
>
> return 0;
> }
> diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c
> index 5772cc5..f265086 100644
> --- a/drivers/watchdog/w83877f_wdt.c
> +++ b/drivers/watchdog/w83877f_wdt.c
> @@ -166,7 +166,7 @@ static void wdt_startup(void)
> static void wdt_turnoff(void)
> {
> /* Stop the timer */
> - del_timer(&timer);
> + del_timer_sync(&timer);
>
> wdt_change(WDT_DISABLE);
>
> --
> 2.6.2
>
