[PATCH v2 2/2] ice: clear Flow Director entries before reset cleanup

[Aaron Ma <aaron.ma@canonical.com>]

Flow Director profiles retain handles to generic flow entries. Reset calls
ice_clear_hw_tbls() to free those entries, but leaves the Flow Director
handles unchanged until replay replaces them.

If rebuild fails before replay completes, later driver removal follows a
stale handle and dereferences a freed flow entry in ice_flow_rem_entry().
KASAN reports a wild access to list poison from
ice_fdir_erase_flow_from_hw().

The failure is reported as:

  KASAN: maybe wild-memory-access in range [0xdead000000000108-...]
  RIP: ice_flow_rem_entry+0xaf/0x170 [ice]
  ice_fdir_erase_flow_from_hw+0x1ee/0x420 [ice]

Clear the Flow Director handles while holding hw->fdir_fltr_lock before
the hardware tables free their entries. A successful replay installs new
handles, while a failed rebuild leaves them invalid for later cleanup.

Fixes: 148beb612031 ("ice: Initialize Flow Director resources")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
---
v1 -> v2:
- Acquire hw->fdir_fltr_lock in ice_fdir_clear_flow_handles() to
  synchronize with concurrent ethtool filter add/del.

 drivers/net/ethernet/intel/ice/ice.h          |  1 +
 .../net/ethernet/intel/ice/ice_ethtool_fdir.c | 26 +++++++++++++++++++
 drivers/net/ethernet/intel/ice/ice_main.c     |  2 ++
 3 files changed, 29 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index db3c7015c56c4..4739ff882b9ec 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -1029,6 +1029,7 @@ ice_get_fdir_fltr_ids(struct ice_hw *hw, struct ethtool_rxnfc *cmd,
 		      u32 *rule_locs);
 void ice_fdir_rem_adq_chnl(struct ice_hw *hw, u16 vsi_idx);
 void ice_fdir_release_flows(struct ice_hw *hw);
+void ice_fdir_clear_flow_handles(struct ice_hw *hw);
 void ice_fdir_replay_flows(struct ice_hw *hw);
 void ice_fdir_replay_fltrs(struct ice_pf *pf);
 int ice_fdir_create_dflt_rules(struct ice_pf *pf);
diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool_fdir.c b/drivers/net/ethernet/intel/ice/ice_ethtool_fdir.c
index aceec184e89b2..04510b36aa56b 100644
--- a/drivers/net/ethernet/intel/ice/ice_ethtool_fdir.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool_fdir.c
@@ -428,6 +428,32 @@ void ice_fdir_release_flows(struct ice_hw *hw)
 		ice_fdir_erase_flow_from_hw(hw, ICE_BLK_FD, flow);
 }
 
+/**
+ * ice_fdir_clear_flow_handles - clear handles freed during reset
+ * @hw: pointer to HW instance
+ */
+void ice_fdir_clear_flow_handles(struct ice_hw *hw)
+{
+	int flow;
+
+	if (!hw->fdir_prof)
+		return;
+
+	mutex_lock(&hw->fdir_fltr_lock);
+	for (flow = 0; flow < ICE_FLTR_PTYPE_MAX; flow++) {
+		struct ice_fd_hw_prof *prof = hw->fdir_prof[flow];
+		int tun, i;
+
+		if (!prof)
+			continue;
+
+		for (tun = 0; tun < ICE_FD_HW_SEG_MAX; tun++)
+			for (i = 0; i < prof->cnt; i++)
+				prof->entry_h[i][tun] = 0;
+	}
+	mutex_unlock(&hw->fdir_fltr_lock);
+}
+
 /**
  * ice_fdir_replay_flows - replay HW Flow Director filter info
  * @hw: pointer to HW instance
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index abb6e850ec09f..164428ba116a0 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -601,6 +601,8 @@ ice_prepare_for_reset(struct ice_pf *pf, enum ice_reset_req reset_type)
 		netif_device_detach(vsi->netdev);
 skip:
 
+	if (hw->fdir_prof)
+		ice_fdir_clear_flow_handles(hw);
 	/* clear SW filtering DB */
 	ice_clear_hw_tbls(hw);
 	/* disable the VSIs and their queues that are not already DOWN */
-- 
2.43.0