diff mbox series

[iwlwifi-next,11/15] wifi: iwlwifi: mld: call thermal exit without wiphy lock held

Message ID 20250506194102.3407967-12-miriam.rachel.korenblit@intel.com
State New
Headers show
Series wifi: iwlwifi: updates - 2025-05-06 | expand

Commit Message

Miri Korenblit May 6, 2025, 7:40 p.m. UTC 
From: Benjamin Berg <benjamin.berg@intel.com>

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>
Message-Id: <20250506223834.30afd080a8a4.I700d0bfef9ff014c19b3e93cb0656195c26b1544@changeid>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/mld/mld.c     | 3 ++-
 drivers/net/wireless/intel/iwlwifi/mld/thermal.c | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/net/wireless/intel/iwlwifi/mld/mld.c b/drivers/net/wireless/intel/iwlwifi/mld/mld.c
index 2c15af7b8768..3e3af7d23b52 100644
--- 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 3232b31f4b0e..f8a8c35066be 100644
--- 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);