On Thu, Apr 21, 2022 at 08:45:34AM -0700, Luck, Tony wrote: > drivers/base/topology.c: In function 'topology_is_visible': > drivers/base/topology.c:158:24: warning: unused variable 'dev' [-Wunused-variable] > 158 | struct device *dev = kobj_to_dev(kobj); > > This is because the topology_ppin(dev->id) macro expands to: > > (cpu_data(dev->id).ppin) > > and with CONFIG_SMP=n the cpu_data() macro expands to boot_cpu_data > (ignoring its argument) with the end result: > > boot_cpu_data.ppin > > My CPP-fu wasn't up to a modification to topology_ppin(), so I added a > (probably redundant) check for "dev" being a NULL pointer. > > Fixes: c3702a746ff5 ("topology/sysfs: Hide PPIN on systems that do not support it.") > Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> > > --- > Better fixes with clever CPP macro tricks gratefully welcomed > --- > drivers/base/topology.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/base/topology.c b/drivers/base/topology.c > index 706dbf8bf249..31fae51fd340 100644 > --- a/drivers/base/topology.c > +++ b/drivers/base/topology.c > @@ -157,7 +157,7 @@ static umode_t topology_is_visible(struct kobject *kobj, > { > struct device *dev = kobj_to_dev(kobj); > > - if (attr == &dev_attr_ppin.attr && !topology_ppin(dev->id)) > + if (!dev || (attr == &dev_attr_ppin.attr && !topology_ppin(dev->id))) !dev is impossible to ever hit, that's the sign that the code is wrong and needs to be fixed :( Sorry, this is not going to be an acceptable change. greg k-h