On Wed, Nov 16, 2016 at 09:46:29PM +0100, Felix Hädicke wrote:
> Add check for NULL before calling kthread_stop().
>
> There were cases in which gserial_console_exit() was called, but the
> console thread was not started. This resulted in an invalid
> kthread_stop(NULL) call.
You can add oops dump in log.
>
> Signed-off-by: Felix Hädicke <felixhaedi...@web.de>
> ---
> drivers/usb/gadget/function/u_serial.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/function/u_serial.c
> b/drivers/usb/gadget/function/u_serial.c
> index 5fedead..f58c775 100644
> --- a/drivers/usb/gadget/function/u_serial.c
> +++ b/drivers/usb/gadget/function/u_serial.c
> @@ -1256,7 +1256,8 @@ static void gserial_console_exit(void)
> struct gscons_info *info = &gscons_info;
>
> unregister_console(&gserial_cons);
> - kthread_stop(info->console_thread);
> + if (info->console_thread != NULL)
if (info->console_thread)
> + kthread_stop(info->console_thread);
> gs_buf_free(&info->con_buf);
> }
>
I can reproduce the NULL pointer dereference problem after enable
g_serial console, and the issue is fixed after applying your patch.
So, Tested-by: Peter Chen <peter.c...@nxp.com>
However, but there is no console enabled information, but console
disabled information is existed like below, I am wondering if it
is a problem.
root@imx6qdlsolo:~# modprobe g_serial
[ 57.305294] g_serial gadget: Gadget Serial v2.4
[ 57.310139] g_serial gadget: g_serial ready
root@imx6qdlsolo:~#
root@imx6qdlsolo:~#
root@imx6qdlsolo:~# modprobe -r g_serial
[ 113.206428] console [ttyGS-1] disabled
--
Best Regards,
Peter Chen
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