On Wed, Feb 17, 2021 at 11:40:00PM +0530, Atul Gopinathan wrote: > On Wed, Feb 17, 2021 at 06:35:15PM +0100, Greg KH wrote: > > On Wed, Feb 17, 2021 at 10:29:08PM +0530, Atul Gopinathan wrote: > > > Resolve the following warning generated by sparse: > > > > > > drivers/staging//comedi/comedi_fops.c:2956:23: warning: incorrect type in > > > assignment (different address spaces) > > > drivers/staging//comedi/comedi_fops.c:2956:23: expected unsigned int > > > *chanlist > > > drivers/staging//comedi/comedi_fops.c:2956:23: got void [noderef] > > > <asn:1> * > > > > > > compat_ptr() has a return type of "void __user *" > > > as defined in "include/linux/compat.h" > > > > > > cmd->chanlist is of type "unsigned int *" as defined > > > in drivers/staging/comedi/comedi.h" in struct > > > comedi_cmd. > > > > > > Signed-off-by: Atul Gopinathan <atulgopinat...@gmail.com> > > > --- > > > drivers/staging/comedi/comedi_fops.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/staging/comedi/comedi_fops.c > > > b/drivers/staging/comedi/comedi_fops.c > > > index e85a99b68f31..fc4ec38012b4 100644 > > > --- a/drivers/staging/comedi/comedi_fops.c > > > +++ b/drivers/staging/comedi/comedi_fops.c > > > @@ -2953,7 +2953,7 @@ static int get_compat_cmd(struct comedi_cmd *cmd, > > > cmd->scan_end_arg = v32.scan_end_arg; > > > cmd->stop_src = v32.stop_src; > > > cmd->stop_arg = v32.stop_arg; > > > - cmd->chanlist = compat_ptr(v32.chanlist); > > > + cmd->chanlist = (unsigned int __force *)compat_ptr(v32.chanlist); > > > > __force? That feels wrong, something is odd if that is ever needed. > > > > Are you _sure_ this is correct? > > The same file has instances of "(usigned int __force *)" cast being > used on the same "cmd->chanlist". For reference: > > At line 1797 of comedi_fops.c: > 1796 /* restore chanlist pointer before copying back */ > 1797 cmd->chanlist = (unsigned int __force *)user_chanlist; > 1798 cmd->data = NULL; > > At line 1880: > 1879 /* restore chanlist pointer before copying back */ > 1880 cmd->chanlist = (unsigned int __force *)user_chanlist; > 1881 *copy = true; > > Here "user_chanlist" is of type "unsigned int __user *". > > > Or perhaps, I shouldn't be relying on them?
I don't know, it still feels wrong. Ian, any thoughts? thanks, greg k-h
