> -----Original Message----- > From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > Sent: Thursday, February 02, 2017 7:14 AM > To: Kershner, David A <David.Kershner@xxxxxxxxxx> > Cc: driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; *S-Par-Maintainer > <SParMaintainer@xxxxxxxxxx>; jes.sorensen@xxxxxxxxx; Binder, David > Anthony <David.Binder@xxxxxxxxxx> > Subject: Re: [PATCH 05/10] staging: unisys: visorbus: Clarify reason for pointer > check in bus_destroy() > > On Wed, Feb 01, 2017 at 05:38:57PM -0500, David Kershner wrote: > > From: David Binder <david.binder@xxxxxxxxxx> > > > > Clarifies why the pointer returned from visorbus_get_device_by_id() in > > bus_destroy() is validated. The check is performed in order to be extra > > careful, for the sake of added security, that the s-Par backend is > > providing us with a valid bus/device pair. > > > > Signed-off-by: David Binder <david.binder@xxxxxxxxxx> > > Signed-off-by: David Kershner <david.kershner@xxxxxxxxxx> > > Reported-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > --- > > drivers/staging/unisys/visorbus/visorchipset.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/staging/unisys/visorbus/visorchipset.c > b/drivers/staging/unisys/visorbus/visorchipset.c > > index c90ea6a..2d1b226 100644 > > --- a/drivers/staging/unisys/visorbus/visorchipset.c > > +++ b/drivers/staging/unisys/visorbus/visorchipset.c > > @@ -755,6 +755,7 @@ bus_destroy(struct controlvm_message *inmsg) > > int err; > > > > bus_info = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, > NULL); > > + /* Validate that s-Par backend gave a good bus */ > > I don't remember what I said in my review, but this comment is pretty > useless. > > I guess my point is, how could BUS_ROOT_DEVICE ever NOT be a valid > device on the bus? What would have made it go away? We are essentially validating "bus_no" here, whose value we just received from the s-Par backend via a message. If bus_no is invalid, i.e., we have no record of a bus with that number ever being created, then visorbus_get_device_by_id() will return NULL. > > Comments like this don't make much sense, maybe my review didn't either > :) > > thanks, > > greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
