* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
@ 2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
` (6 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
2025-06-17 8:49 ` [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch syzbot
@ 2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
` (5 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
2025-06-17 8:49 ` [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch syzbot
2025-06-17 8:49 ` syzbot
@ 2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
` (4 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
` (2 preceding siblings ...)
2025-06-17 8:49 ` syzbot
@ 2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
` (3 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
` (3 preceding siblings ...)
2025-06-17 8:49 ` syzbot
@ 2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
` (2 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
` (4 preceding siblings ...)
2025-06-17 8:49 ` syzbot
@ 2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
` (5 preceding siblings ...)
2025-06-17 8:49 ` syzbot
@ 2025-06-17 8:49 ` syzbot
2025-06-17 8:49 ` syzbot
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH wireless] wifi: mac80211: don't WARN for late channel/color switch
[not found] <20250617104902.146e10919be1.I85f352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid>
` (6 preceding siblings ...)
2025-06-17 8:49 ` syzbot
@ 2025-06-17 8:49 ` syzbot
7 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2025-06-17 8:49 UTC (permalink / raw)
To: johannes
Cc: johannes.berg, johannes, linux-wireless, linux-kernel, syzkaller-bugs
> From: Johannes Berg <johannes.berg@intel.com>
>
> There's really no value in the WARN stack trace etc., the reason
> for this happening isn't directly related to the calling function
> anyway. Also, syzbot has been observing it constantly, and there's
> no way we can resolve it there - those systems are just slow.
>
> Instead print an error message (once) and add a comment about what
> really causes this message.
>
> Reported-by: syzbot+468656785707b0e995df@syzkaller.appspotmail.com
> Reported-by: syzbot+18c783c5cf6a781e3e2c@syzkaller.appspotmail.com
> Reported-by: syzbot+d5924d5cffddfccab68e@syzkaller.appspotmail.com
> Reported-by: syzbot+7d73d99525d1ff7752ef@syzkaller.appspotmail.com
> Reported-by: syzbot+8e6e002c74d1927edaf5@syzkaller.appspotmail.com
> Reported-by: syzbot+97254a3b10c541879a65@syzkaller.appspotmail.com
> Reported-by: syzbot+dfd1fd46a1960ad9c6ec@syzkaller.appspotmail.com
> Reported-by: syzbot+85e0b8d12d9ca877d806@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> #syz test
This crash does not have a reproducer. I cannot test it.
> ---
> net/mac80211/debug.h | 5 ++++-
> net/mac80211/tx.c | 29 +++++++++++++++++++++--------
> 2 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/net/mac80211/debug.h b/net/mac80211/debug.h
> index 5b81998cb0c9..ef7c1a68d88d 100644
> --- a/net/mac80211/debug.h
> +++ b/net/mac80211/debug.h
> @@ -1,10 +1,11 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> /*
> * Portions
> - * Copyright (C) 2022 - 2024 Intel Corporation
> + * Copyright (C) 2022 - 2025 Intel Corporation
> */
> #ifndef __MAC80211_DEBUG_H
> #define __MAC80211_DEBUG_H
> +#include <linux/once_lite.h>
> #include <net/cfg80211.h>
>
> #ifdef CONFIG_MAC80211_OCB_DEBUG
> @@ -152,6 +153,8 @@ do { \
> else \
> _sdata_err((link)->sdata, fmt, ##__VA_ARGS__); \
> } while (0)
> +#define link_err_once(link, fmt, ...) \
> + DO_ONCE_LITE(link_err, link, fmt, ##__VA_ARGS__)
> #define link_id_info(sdata, link_id, fmt, ...) \
> do { \
> if (ieee80211_vif_is_mld(&sdata->vif)) \
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index d8d4f3d7d7f2..d58b80813bdd 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -5,7 +5,7 @@
> * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
> * Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
> * Copyright 2013-2014 Intel Mobile Communications GmbH
> - * Copyright (C) 2018-2024 Intel Corporation
> + * Copyright (C) 2018-2025 Intel Corporation
> *
> * Transmit and frame generation functions.
> */
> @@ -5016,12 +5016,25 @@ static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
> }
> }
>
> -static u8 __ieee80211_beacon_update_cntdwn(struct beacon_data *beacon)
> +static u8 __ieee80211_beacon_update_cntdwn(struct ieee80211_link_data *link,
> + struct beacon_data *beacon)
> {
> - beacon->cntdwn_current_counter--;
> + if (beacon->cntdwn_current_counter == 1) {
> + /*
> + * Channel switch handling is done by a worker thread while
> + * beacons get pulled from hardware timers. It's therefore
> + * possible that software threads are slow enough to not be
> + * able to complete CSA handling in a single beacon interval,
> + * in which case we get here. There isn't much to do about
> + * it, other than letting the user know that the AP isn't
> + * behaving correctly.
> + */
> + link_err_once(link,
> + "beacon TX faster than countdown (channel/color switch) completion\n");
> + return 0;
> + }
>
> - /* the counter should never reach 0 */
> - WARN_ON_ONCE(!beacon->cntdwn_current_counter);
> + beacon->cntdwn_current_counter--;
>
> return beacon->cntdwn_current_counter;
> }
> @@ -5052,7 +5065,7 @@ u8 ieee80211_beacon_update_cntdwn(struct ieee80211_vif *vif, unsigned int link_i
> if (!beacon)
> goto unlock;
>
> - count = __ieee80211_beacon_update_cntdwn(beacon);
> + count = __ieee80211_beacon_update_cntdwn(link, beacon);
>
> unlock:
> rcu_read_unlock();
> @@ -5450,7 +5463,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
>
> if (beacon->cntdwn_counter_offsets[0]) {
> if (!is_template)
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> @@ -5482,7 +5495,7 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
> * for now we leave it consistent with overall
> * mac80211's behavior.
> */
> - __ieee80211_beacon_update_cntdwn(beacon);
> + __ieee80211_beacon_update_cntdwn(link, beacon);
>
> ieee80211_set_beacon_cntdwn(sdata, beacon, link);
> }
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread