Re: [PATCH] wifi: iwlwifi: use unique thermal zone type

[Jiajia Liu]

On Tue, Jul 14, 2026 at 06:58:40PM +0000, Korenblit, Miriam Rachel wrote:
> 
> 
> > -----Original Message-----
> > From: Jiajia Liu <liujiajia@xxxxxxxxxx>
> > Sent: Thursday, March 12, 2026 3:41 AM
> > To: Korenblit, Miriam Rachel <miriam.rachel.korenblit@xxxxxxxxx>; Berg,
> > Benjamin <benjamin.berg@xxxxxxxxx>; Berg, Johannes
> > <johannes.berg@xxxxxxxxx>; linux-wireless@xxxxxxxxxxxxxxx; linux-
> > kernel@xxxxxxxxxxxxxxx
> > Cc: Jiajia Liu <liujiajia@xxxxxxxxxx>
> > Subject: [PATCH] wifi: iwlwifi: use unique thermal zone type
> > 
> > Unloading iwlmld or iwlmvm can trigger hung task when two devices using
> > iwlmvm and iwlmld respectively on one setup. Their thermal zones have the
> > same type and share the same hwmon device created by the first zone. The
> > second zone indirectly holds the first zone through hwmon and prevents the first
> > zone from unregistering.
> > Tested with AX211 (8086:7af0) and BE200 (8086:272b).
> > 
> > INFO: task modprobe:5295 blocked for more than 120 seconds.
> >       Not tainted 7.0.0-rc2-up1 #2
> > Call Trace:
> >  __schedule+0x4df/0xfd0
> >  schedule+0x27/0xd0
> >  schedule_timeout+0xbd/0x100
> >  __wait_for_common+0x97/0x1b0
> >  ? __pfx_schedule_timeout+0x10/0x10
> >  thermal_zone_device_unregister+0x173/0x1c0
> >  iwl_mld_thermal_exit+0xbb/0xd0 [iwlmld]
> >  iwl_op_mode_mld_stop+0x37/0x120 [iwlmld]
> >  iwl_opmode_deregister+0xc0/0x160 [iwlwifi]
> >  __do_sys_delete_module+0x1b5/0x320
> > 
> > Signed-off-by: Jiajia Liu <liujiajia@xxxxxxxxxx>
> > ---
> >  drivers/net/wireless/intel/iwlwifi/iwl-utils.c   | 10 ++++++++++
> >  drivers/net/wireless/intel/iwlwifi/iwl-utils.h   |  4 ++++
> >  drivers/net/wireless/intel/iwlwifi/mld/thermal.c |  4 ++--
> >  drivers/net/wireless/intel/iwlwifi/mvm/tt.c      |  6 ++++--
> >  4 files changed, 20 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-utils.c
> > b/drivers/net/wireless/intel/iwlwifi/iwl-utils.c
> > index d503544fda40..fe5fa5e59664 100644
> > --- a/drivers/net/wireless/intel/iwlwifi/iwl-utils.c
> > +++ b/drivers/net/wireless/intel/iwlwifi/iwl-utils.c
> > @@ -193,3 +193,13 @@ s8 iwl_average_neg_dbm(const u8 *neg_dbm_values,
> > u8 len)
> >  	return clamp(average_magnitude - i, -128, 0);  }
> > IWL_EXPORT_SYMBOL(iwl_average_neg_dbm);
> > +
> > +#ifdef CONFIG_THERMAL
> > +u8 iwl_thermal_zone_get_id(void)
> > +{
> > +	static atomic_t counter = ATOMIC_INIT(0);
> > +
> > +	return atomic_inc_return(&counter) & 0xFF; }
> > +IWL_EXPORT_SYMBOL(iwl_thermal_zone_get_id);
> > +#endif
> > diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-utils.h
> > b/drivers/net/wireless/intel/iwlwifi/iwl-utils.h
> > index 5172035e4d26..84a4543fd290 100644
> > --- a/drivers/net/wireless/intel/iwlwifi/iwl-utils.h
> > +++ b/drivers/net/wireless/intel/iwlwifi/iwl-utils.h
> > @@ -55,4 +55,8 @@ u32 iwl_find_ie_offset(u8 *beacon, u8 eid, u32 frame_size)
> > 
> >  s8 iwl_average_neg_dbm(const u8 *neg_dbm_values, u8 len);
> > 
> > +#ifdef CONFIG_THERMAL
> > +u8 iwl_thermal_zone_get_id(void);
> > +#endif
> > +
> >  #endif /* __iwl_utils_h__ */
> > diff --git a/drivers/net/wireless/intel/iwlwifi/mld/thermal.c
> > b/drivers/net/wireless/intel/iwlwifi/mld/thermal.c
> > index f8a8c35066be..500028a4dbd3 100644
> > --- a/drivers/net/wireless/intel/iwlwifi/mld/thermal.c
> > +++ b/drivers/net/wireless/intel/iwlwifi/mld/thermal.c
> > @@ -5,6 +5,7 @@
> >  #ifdef CONFIG_THERMAL
> >  #include <linux/sort.h>
> >  #include <linux/thermal.h>
> > +#include "iwl-utils.h"
> >  #endif
> > 
> >  #include "fw/api/phy.h"
> > @@ -243,7 +244,6 @@ static void iwl_mld_thermal_zone_register(struct
> > iwl_mld *mld)  {
> >  	int ret;
> >  	char name[16];
> > -	static atomic_t counter = ATOMIC_INIT(0);
> >  	struct thermal_trip trips[IWL_MAX_DTS_TRIPS] = {
> >  		[0 ... IWL_MAX_DTS_TRIPS - 1] = {
> >  			.temperature = THERMAL_TEMP_INVALID, @@ -254,7
> > +254,7 @@ static void iwl_mld_thermal_zone_register(struct iwl_mld *mld)
> > 
> >  	BUILD_BUG_ON(ARRAY_SIZE(name) >= THERMAL_NAME_LENGTH);
> > 
> > -	sprintf(name, "iwlwifi_%u", atomic_inc_return(&counter) & 0xFF);
> Any reason not to have iwlmld (and iwlmvm in mvm) instead of a shared counter?

I was not sure if it would break user space.

This issue is fixed by thermal hwmon at

https://lore.kernel.org/linux-pm/6017595.DvuYhMxLoT@rafael.j.wysocki/

with commit d6323469bcfb ("thermal: hwmon: Register a hwmon device for each thermal zone") in v7.2-rc1.

> 
> > +	sprintf(name, "iwlwifi_%u", iwl_thermal_zone_get_id());
> >  	mld->tzone =
> >  		thermal_zone_device_register_with_trips(name, trips,
> >  							IWL_MAX_DTS_TRIPS,
> > diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
> > b/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
> > index 53bab21ebae2..ea8e616174db 100644
> > --- a/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
> > +++ b/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
> > @@ -7,6 +7,9 @@
> >  #include <linux/sort.h>
> > 
> >  #include "mvm.h"
> > +#ifdef CONFIG_THERMAL
> > +#include "iwl-utils.h"
> > +#endif
> > 
> >  #define IWL_MVM_NUM_CTDP_STEPS		20
> >  #define IWL_MVM_MIN_CTDP_BUDGET_MW	150
> > @@ -652,7 +655,6 @@ static void iwl_mvm_thermal_zone_register(struct
> > iwl_mvm *mvm)  {
> >  	int i, ret;
> >  	char name[16];
> > -	static atomic_t counter = ATOMIC_INIT(0);
> > 
> >  	if (!iwl_mvm_is_tt_in_fw(mvm)) {
> >  		mvm->tz_device.tzone = NULL;
> > @@ -662,7 +664,7 @@ static void iwl_mvm_thermal_zone_register(struct
> > iwl_mvm *mvm)
> > 
> >  	BUILD_BUG_ON(ARRAY_SIZE(name) >= THERMAL_NAME_LENGTH);
> > 
> > -	sprintf(name, "iwlwifi_%u", atomic_inc_return(&counter) & 0xFF);
> > +	sprintf(name, "iwlwifi_%u", iwl_thermal_zone_get_id());
> >  	/*
> >  	 * 0 is a valid temperature,
> >  	 * so initialize the array with S16_MIN which invalid temperature
> > --
> > 2.53.0
>