Unloading the ice driver while switchdev port representors are added to
a bridge can lead to kernel panic. Reproducer:
modprobe ice
devlink dev eswitch set $PF1_PCI mode switchdev
ip link add $BR type bridge
ip link set $BR up
echo 2 > /sys/class/net/$PF1/device/sriov_numvfs
sleep 2
ip link set $PF1 master $BR
ip link set $VF1_PR master $BR
ip link set $VF2_PR master $BR
ip link set $PF1 up
ip link set $VF1_PR up
ip link set $VF2_PR up
ip link set $VF1 up
rmmod irdma ice
When unloading the driver, ice_eswitch_detach() is eventually called as
part of VF freeing. First, it removes a port representor from xarray,
then unregister_netdev() is called (via repr->ops.rem()), finally
representor is deallocated. The problem comes from the bridge doing its
own deinit at the same time. unregister_netdev() triggers a notifier
chain, resulting in ice_eswitch_br_port_deinit() being called. It should
set repr->br_port = NULL, but this does not happen since repr has
already been removed from xarray and is not found. Regardless, it
finishes up deallocating br_port. At this point, repr is still not freed
and an fdb event can happen, in which ice_eswitch_br_fdb_event_work()
takes repr->br_port and tries to use it, which causes a panic (use after
free).
Note that this only happens with 2 or more port representors added to
the bridge, since with only one representor port, the bridge deinit is
slightly different (ice_eswitch_br_port_deinit() is called via
ice_eswitch_br_ports_flush(), not ice_eswitch_br_port_unlink()).
A workaround is available: brctl setageing $BR 0, which stops the bridge
from adding fdb entries altogether.
Change the order of operations in ice_eswitch_detach(): move the call to
unregister_netdev() before removing repr from xarray. This way
repr->br_port will be correctly set to NULL in
ice_eswitch_br_port_deinit(), preventing a panic.
Fixes: fff292b47ac1 ("ice: add VF representors one by one")
Reviewed-by: Michal Swiatkowski <michal.swiatkow...@linux.intel.com>
Signed-off-by: Marcin Szycik <marcin.szy...@linux.intel.com>
---
drivers/net/ethernet/intel/ice/ice_eswitch.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_eswitch.c
b/drivers/net/ethernet/intel/ice/ice_eswitch.c
index c0b3e70a7ea3..fb527434b58b 100644
--- a/drivers/net/ethernet/intel/ice/ice_eswitch.c
+++ b/drivers/net/ethernet/intel/ice/ice_eswitch.c
@@ -552,13 +552,14 @@ int ice_eswitch_attach_sf(struct ice_pf *pf, struct
ice_dynamic_port *sf)
static void ice_eswitch_detach(struct ice_pf *pf, struct ice_repr *repr)
{
ice_eswitch_stop_reprs(pf);
+ repr->ops.rem(repr);
+
xa_erase(&pf->eswitch.reprs, repr->id);
if (xa_empty(&pf->eswitch.reprs))
ice_eswitch_disable_switchdev(pf);
ice_eswitch_release_repr(pf, repr);
- repr->ops.rem(repr);
ice_repr_destroy(repr);
if (xa_empty(&pf->eswitch.reprs)) {
--
2.45.0
