[PATCH iwl-net v4 4/6] ice: check ICE_VSI_DOWN under rtnl_lock when preparing for reset

Larysa Zaremba
2024-08-23T10:08:09Z

Consider the following scenario:

.ndo_bpf() | ice_prepare_for_reset() |
________________________|_______________________________________|
rtnl_lock() | |
ice_down() | |
| test_bit(ICE_VSI_DOWN) - true |
| ice_dis_vsi() returns |
ice_up() | |
| proceeds to rebuild a running VSI |

.ndo_bpf() is not the only rtnl-locked callback that toggles the interface
to apply new configuration. Another example is .set_channels().

To avoid the race condition above, act only after reading ICE_VSI_DOWN
under rtnl_lock.

Fixes: 0f9d5027a749 ("ice: Refactor VSI allocation, deletion and rebuild flow")
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
---
drivers/net/ethernet/intel/ice/ice_lib.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 14257e036d4b..2405e5ed9128 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2665,8 +2665,7 @@ int ice_ena_vsi(struct ice_vsi *vsi, bool locked)
*/
void ice_dis_vsi(struct ice_vsi *vsi, bool locked)
{
- if (test_bit(ICE_VSI_DOWN, vsi->state))
- return;
+ bool already_down = test_bit(ICE_VSI_DOWN, vsi->state);

set_bit(ICE_VSI_NEEDS_RESTART, vsi->state);

@@ -2674,15 +2673,16 @@ void ice_dis_vsi(struct ice_vsi *vsi, bool locked)
if (netif_running(vsi->netdev)) {
if (!locked)
rtnl_lock();
-
- ice_vsi_close(vsi);
+ already_down = test_bit(ICE_VSI_DOWN, vsi->state);
+ if (!already_down)
+ ice_vsi_close(vsi);

if (!locked)
rtnl_unlock();
- } else {
+ } else if (!already_down) {
ice_vsi_close(vsi);
}
- } else if (vsi->type == ICE_VSI_CTRL) {
+ } else if (vsi->type == ICE_VSI_CTRL && !already_down) {
ice_vsi_close(vsi);
}
}
--
2.43.0