On Sat, Jun 04, 2022 at 10:54:54AM +0800, Linyu Yuan wrote:
> If a task read/write data in blocking mode, it will wait the completion
> in ffs_epfile_io(), if function unbind occurs, ffs_func_unbind() will
> kfree ffs ep, once the task wake up, it still dereference the ffs ep to
> obtain the request status.
>
> Fix it by moving the request status to io_data which is stack-safe.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.15
> Reported-by: Michael Wu <michael@xxxxxxxxxxxxxxxxx>
> Tested-by: Michael Wu <michael@xxxxxxxxxxxxxxxxx>
> Reviewed-by: John Keeping <john@xxxxxxxxxxxx>
> Signed-off-by: Linyu Yuan <quic_linyyuan@xxxxxxxxxxx>
> ---
> v2: correct interrupted assignment
> v3: add Reviewed-by and Reported-by
> v4: add Tetsed-by from Michael Wu,
> remove one empty line
> cc stable kernel
>
> drivers/usb/gadget/function/f_fs.c | 31 ++++++++++++++++---------------
> 1 file changed, 16 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index 4585ee3..3958c60 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -122,8 +122,6 @@ struct ffs_ep {
> struct usb_endpoint_descriptor *descs[3];
>
> u8 num;
> -
> - int status; /* P: epfile->mutex */
> };
>
> struct ffs_epfile {
> @@ -227,6 +225,9 @@ struct ffs_io_data {
> bool use_sg;
>
> struct ffs_data *ffs;
> +
> + int status;
> + struct completion done;
> };
>
> struct ffs_desc_helper {
> @@ -707,12 +708,12 @@ static const struct file_operations ffs_ep0_operations = {
>
> static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
> {
> + struct ffs_io_data *io_data = req->context;
> +
> ENTER();
> - if (req->context) {
> - struct ffs_ep *ep = _ep->driver_data;
> - ep->status = req->status ? req->status : req->actual;
> - complete(req->context);
> - }
> +
> + io_data->status = req->status ? req->status : req->actual;
Please do not use ? : lines unless you have to. Please write this as
normal if () lines.
thanks,
greg k-h
