wifi: iwlwifi: mld: call thermal exit without wiphy lock held

The driver must not hold the wiphy mutex when unregistering the thermal
devices. Do not hold the lock for the call to iwl_mld_thermal_exit and
only do a lock/unlock to cancel the ct_kill_exit_wk work.

The problem is that iwl_mld_tzone_get_temp needs to take the wiphy lock
while the thermal code is holding its own locks already. When
unregistering the device, the reverse would happen as the driver was
calling thermal_cooling_device_unregister with the wiphy mutex already
held.

It is not likely to trigger this deadlock as it can only happen if the
thermal code is polling the temperature while the driver is being
unloaded. However, lockdep reported it so fix it.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20250506194102.3407967-12-miriam.rachel.korenblit@intel.com
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mld/mld.c b/drivers/net/wireless/intel/iwlwifi/mld/mld.c
index 2c15af7b8768d933b563448f5e64bd171ed4cacb..3e3af7d23b52a3fc46efd10ab5b4783a90575c82 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mld/mld.c
+++ b/drivers/net/wireless/intel/iwlwifi/mld/mld.c
@@ -489,8 +489,9 @@ iwl_op_mode_mld_stop(struct iwl_op_mode *op_mode)
        iwl_mld_ptp_remove(mld);
        iwl_mld_leds_exit(mld);
 
-       wiphy_lock(mld->wiphy);
        iwl_mld_thermal_exit(mld);
+
+       wiphy_lock(mld->wiphy);
        iwl_mld_low_latency_stop(mld);
        iwl_mld_deinit_time_sync(mld);
        wiphy_unlock(mld->wiphy);

diff --git a/drivers/net/wireless/intel/iwlwifi/mld/thermal.c b/drivers/net/wireless/intel/iwlwifi/mld/thermal.c
index 3232b31f4b0e97c712626ac183ada207764ca7e0..f8a8c35066beb21891b4f4aecab64bb9ff6b167c 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mld/thermal.c
+++ b/drivers/net/wireless/intel/iwlwifi/mld/thermal.c
@@ -441,6 +441,8 @@ static u32 iwl_mld_ctdp_get_max_budget(struct iwl_mld *mld)
 
 void iwl_mld_thermal_initialize(struct iwl_mld *mld)
 {
+       lockdep_assert_not_held(&mld->wiphy->mtx);
+
        wiphy_delayed_work_init(&mld->ct_kill_exit_wk, iwl_mld_exit_ctkill);
 
        mld->power_budget_mw = iwl_mld_ctdp_get_max_budget(mld);
@@ -454,7 +456,9 @@ void iwl_mld_thermal_initialize(struct iwl_mld *mld)
 
 void iwl_mld_thermal_exit(struct iwl_mld *mld)
 {
+       wiphy_lock(mld->wiphy);
        wiphy_delayed_work_cancel(mld->wiphy, &mld->ct_kill_exit_wk);
+       wiphy_unlock(mld->wiphy);
 
 #ifdef CONFIG_THERMAL
        iwl_mld_cooling_device_unregister(mld);