Call to ieee80211_color_collision_detection_work() needs wiphy lock to be held (see lockdep assert in cfg80211_bss_color_notify()). Not locking wiphy causes the following lockdep error: WARNING: CPU: 2 PID: 42 at net/wireless/nl80211.c:19505 cfg80211_bss_color_notify+0x1a4/0x25c Modules linked in: CPU: 2 PID: 42 Comm: kworker/u8:3 Tainted: G W 6.4.0-02327-g36c6cb260481 #1048 Hardware name: Workqueue: phy1 ieee80211_color_collision_detection_work pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : cfg80211_bss_color_notify+0x1a4/0x25c lr : cfg80211_bss_color_notify+0x1a0/0x25c sp : ffff000002947d00 x29: ffff000002947d00 x28: ffff800008e1a000 x27: ffff000002bd4705 x26: ffff00000d034000 x25: ffff80000903cf40 x24: 0000000000000000 x23: ffff00000cb70720 x22: 0000000000800000 x21: ffff800008dfb008 x20: 000000000000008d x19: ffff00000d035fa8 x18: 0000000000000010 x17: 0000000000000001 x16: 000003564b1ce96a x15: 000d69696d057970 x14: 000000000000003b x13: 0000000000000001 x12: 0000000000040000 x11: 0000000000000001 x10: ffff80000978f9c0 x9 : ffff0000028d3174 x8 : ffff800008e30000 x7 : 0000000000000000 x6 : 0000000000000028 x5 : 000000000002f498 x4 : ffff00000d034a80 x3 : 0000000000800000 x2 : ffff800016143000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: cfg80211_bss_color_notify+0x1a4/0x25c ieee80211_color_collision_detection_work+0x20/0x118 process_one_work+0x294/0x554 worker_thread+0x70/0x440 kthread+0xf4/0xf8 ret_from_fork+0x10/0x20 irq event stamp: 77372 hardirqs last enabled at (77371): [<ffff800008a346fc>] _raw_spin_unlock_irq+0x2c/0x4c hardirqs last disabled at (77372): [<ffff800008a28754>] el1_dbg+0x20/0x48 softirqs last enabled at (77350): [<ffff8000089e120c>] batadv_send_outstanding_bcast_packet+0xb8/0x120 softirqs last disabled at (77348): [<ffff8000089e11d4>] batadv_send_outstanding_bcast_packet+0x80/0x120 The wiphy lock cannot be taken directly from color collision detection delayed work (ieee80211_color_collision_detection_work()) because this work is cancel_delayed_work_sync() under this wiphy lock causing a potential deadlock( see [0] for details). To fix that ieee80211_color_collision_detection_work() could be converted to a wiphy work and cancel_delayed_work_sync() can be simply replaced by wiphy_delayed_work_cancel() serving the same purpose under wiphy lock. This could potentially fix [1]. [0]: https://lore.kernel.org/linux-wireless/D4A40Q44OAY2.W3SIF6UEPBUN@xxxxxxxxxx/ [1]: https://lore.kernel.org/lkml/000000000000612f290618eee3e5@xxxxxxxxxx/ Reported-by: Nicolas Escande <nescande@xxxxxxxxxx> Signed-off-by: Remi Pommarel <repk@xxxxxxxxxxxx> --- net/mac80211/cfg.c | 17 +++++++++-------- net/mac80211/ieee80211_i.h | 5 +++-- net/mac80211/link.c | 7 ++++--- 3 files changed, 16 insertions(+), 13 deletions(-) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index b02b84ce2130..09025d59cdbe 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -4819,12 +4819,12 @@ void ieee80211_color_change_finalize_work(struct wiphy *wiphy, ieee80211_color_change_finalize(link); } -void ieee80211_color_collision_detection_work(struct work_struct *work) +void ieee80211_color_collision_detection_work(struct wiphy *wiphy, + struct wiphy_work *work) { - struct delayed_work *delayed_work = to_delayed_work(work); struct ieee80211_link_data *link = - container_of(delayed_work, struct ieee80211_link_data, - color_collision_detect_work); + container_of(work, struct ieee80211_link_data, + color_collision_detect_work.work); struct ieee80211_sub_if_data *sdata = link->sdata; cfg80211_obss_color_collision_notify(sdata->dev, link->color_bitmap, @@ -4877,7 +4877,8 @@ ieee80211_obss_color_collision_notify(struct ieee80211_vif *vif, return; } - if (delayed_work_pending(&link->color_collision_detect_work)) { + if (wiphy_delayed_work_pending(sdata->local->hw.wiphy, + &link->color_collision_detect_work)) { rcu_read_unlock(); return; } @@ -4886,9 +4887,9 @@ ieee80211_obss_color_collision_notify(struct ieee80211_vif *vif, /* queue the color collision detection event every 500 ms in order to * avoid sending too much netlink messages to userspace. */ - ieee80211_queue_delayed_work(&sdata->local->hw, - &link->color_collision_detect_work, - msecs_to_jiffies(500)); + wiphy_delayed_work_queue(sdata->local->hw.wiphy, + &link->color_collision_detect_work, + msecs_to_jiffies(500)); rcu_read_unlock(); } diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index a3485e4c6132..8650b3e8f1a9 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1051,7 +1051,7 @@ struct ieee80211_link_data { } csa; struct wiphy_work color_change_finalize_work; - struct delayed_work color_collision_detect_work; + struct wiphy_delayed_work color_collision_detect_work; u64 color_bitmap; /* context reservation -- protected with wiphy mutex */ @@ -2004,7 +2004,8 @@ int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev, /* color change handling */ void ieee80211_color_change_finalize_work(struct wiphy *wiphy, struct wiphy_work *work); -void ieee80211_color_collision_detection_work(struct work_struct *work); +void ieee80211_color_collision_detection_work(struct wiphy *wiphy, + struct wiphy_work *work); /* interface handling */ #define MAC80211_SUPPORTED_FEATURES_TX (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM | \ diff --git a/net/mac80211/link.c b/net/mac80211/link.c index 1a211b8d4057..67f65ff79a71 100644 --- a/net/mac80211/link.c +++ b/net/mac80211/link.c @@ -41,8 +41,8 @@ void ieee80211_link_init(struct ieee80211_sub_if_data *sdata, ieee80211_csa_finalize_work); wiphy_work_init(&link->color_change_finalize_work, ieee80211_color_change_finalize_work); - INIT_DELAYED_WORK(&link->color_collision_detect_work, - ieee80211_color_collision_detection_work); + wiphy_delayed_work_init(&link->color_collision_detect_work, + ieee80211_color_collision_detection_work); INIT_LIST_HEAD(&link->assigned_chanctx_list); INIT_LIST_HEAD(&link->reserved_chanctx_list); @@ -70,7 +70,8 @@ void ieee80211_link_stop(struct ieee80211_link_data *link) if (link->sdata->vif.type == NL80211_IFTYPE_STATION) ieee80211_mgd_stop_link(link); - cancel_delayed_work_sync(&link->color_collision_detect_work); + wiphy_delayed_work_cancel(link->sdata->local->hw.wiphy, + &link->color_collision_detect_work); wiphy_work_cancel(link->sdata->local->hw.wiphy, &link->color_change_finalize_work); wiphy_work_cancel(link->sdata->local->hw.wiphy, -- 2.46.0
