Re: [BUGFIX PATCH] USB: chipidea: fix use after free bug

[Alexander Shishkin <alexander.shishkin@linux.intel.com>]

Lothar Waßmann <LW@KARO-electronics.de> writes:

> The pointer to a platform_device struct must not be dereferenced after
> the device has been unregistered.
>
> This bug produces a crash when unloading the ci13xxx kernel module
> compiled with CONFIG_PAGE_POISONING enabled.
>
> Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>

Good one, thanks.

Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>

Greg, this is -stable material, applicable starting from v3.6.

> ---
>  drivers/usb/chipidea/core.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> index f69d029..b726c49 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -385,8 +385,9 @@ EXPORT_SYMBOL_GPL(ci13xxx_add_device);
>  
>  void ci13xxx_remove_device(struct platform_device *pdev)
>  {
> +	int id = pdev->id;
>  	platform_device_unregister(pdev);
> -	ida_simple_remove(&ci_ida, pdev->id);
> +	ida_simple_remove(&ci_ida, id);
>  }
>  EXPORT_SYMBOL_GPL(ci13xxx_remove_device);
>  
> -- 
> 1.7.2.5