On Mon, Dec 12, 2022 at 06:54:24PM +0530, Prashanth K wrote: > Function pointer ki_complete() expects 'long' as its second > argument, but we pass integer from ffs_user_copy_worker. This > might cause a CFI failure, as ki_complete is an indirect call > with mismatched prototype. Fix this by typecasting the second > argument to long. "might"? Does it or not? If it does, why hasn't this been reported before? > Cc: <stable@xxxxxxxxxxxxxxx> # 5.15 CFI first showed up in 6.1, not 5.15, right? > Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx> > > --- > drivers/usb/gadget/function/f_fs.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c > index 73dc10a7..9c26561 100644 > --- a/drivers/usb/gadget/function/f_fs.c > +++ b/drivers/usb/gadget/function/f_fs.c > @@ -835,7 +835,7 @@ static void ffs_user_copy_worker(struct work_struct *work) > kthread_unuse_mm(io_data->mm); > } > > - io_data->kiocb->ki_complete(io_data->kiocb, ret); > + io_data->kiocb->ki_complete(io_data->kiocb, (long)ret); Why just fix up this one instance? What about ep_user_copy_worker()? And what about all other calls to ki_complete that are not using a (long) cast? This feels wrong, what exactly is the reported error and how come other kernel calls to this function pointer have not had a problem with CFI? ceph_aio_complete() would be another example, right? thanks, greg k-h
