From: Alexander Wetzel Alexander@wetzel-home.de
[ Upstream commit 2c5dee15239f3f3e31aa5c8808f18996c039e2c1 ]
Callers of wdev_chandef() must hold the wiphy mutex.
But the worker cfg80211_propagate_cac_done_wk() never takes the lock. Which triggers the warning below with the mesh_peer_connected_dfs test from hostapd and not (yet) released mac80211 code changes:
WARNING: CPU: 0 PID: 495 at net/wireless/chan.c:1552 wdev_chandef+0x60/0x165 Modules linked in: CPU: 0 UID: 0 PID: 495 Comm: kworker/u4:2 Not tainted 6.14.0-rc5-wt-g03960e6f9d47 #33 13c287eeabfe1efea01c0bcc863723ab082e17cf Workqueue: cfg80211 cfg80211_propagate_cac_done_wk Stack: 00000000 00000001 ffffff00 6093267c 00000000 6002ec30 6d577c50 60037608 00000000 67e8d108 6063717b 00000000 Call Trace: [<6002ec30>] ? _printk+0x0/0x98 [<6003c2b3>] show_stack+0x10e/0x11a [<6002ec30>] ? _printk+0x0/0x98 [<60037608>] dump_stack_lvl+0x71/0xb8 [<6063717b>] ? wdev_chandef+0x60/0x165 [<6003766d>] dump_stack+0x1e/0x20 [<6005d1b7>] __warn+0x101/0x20f [<6005d3a8>] warn_slowpath_fmt+0xe3/0x15d [<600b0c5c>] ? mark_lock.part.0+0x0/0x4ec [<60751191>] ? __this_cpu_preempt_check+0x0/0x16 [<600b11a2>] ? mark_held_locks+0x5a/0x6e [<6005d2c5>] ? warn_slowpath_fmt+0x0/0x15d [<60052e53>] ? unblock_signals+0x3a/0xe7 [<60052f2d>] ? um_set_signals+0x2d/0x43 [<60751191>] ? __this_cpu_preempt_check+0x0/0x16 [<607508b2>] ? lock_is_held_type+0x207/0x21f [<6063717b>] wdev_chandef+0x60/0x165 [<605f89b4>] regulatory_propagate_dfs_state+0x247/0x43f [<60052f00>] ? um_set_signals+0x0/0x43 [<605e6bfd>] cfg80211_propagate_cac_done_wk+0x3a/0x4a [<6007e460>] process_scheduled_works+0x3bc/0x60e [<6007d0ec>] ? move_linked_works+0x4d/0x81 [<6007d120>] ? assign_work+0x0/0xaa [<6007f81f>] worker_thread+0x220/0x2dc [<600786ef>] ? set_pf_worker+0x0/0x57 [<60087c96>] ? to_kthread+0x0/0x43 [<6008ab3c>] kthread+0x2d3/0x2e2 [<6007f5ff>] ? worker_thread+0x0/0x2dc [<6006c05b>] ? calculate_sigpending+0x0/0x56 [<6003b37d>] new_thread_handler+0x4a/0x64 irq event stamp: 614611 hardirqs last enabled at (614621): [<00000000600bc96b>] __up_console_sem+0x82/0xaf hardirqs last disabled at (614630): [<00000000600bc92c>] __up_console_sem+0x43/0xaf softirqs last enabled at (614268): [<00000000606c55c6>] __ieee80211_wake_queue+0x933/0x985 softirqs last disabled at (614266): [<00000000606c52d6>] __ieee80211_wake_queue+0x643/0x985
Fixes: 26ec17a1dc5e ("cfg80211: Fix radar event during another phy CAC") Signed-off-by: Alexander Wetzel Alexander@wetzel-home.de Link: https://patch.msgid.link/20250717162547.94582-1-Alexander@wetzel-home.de Signed-off-by: Johannes Berg johannes.berg@intel.com [ The author recommends that when porting to older kernels, we should use wiphy_lock() and wiphy_unlock() instead of guard(). This tip is mentioned in the link: https://patch.msgid.link/20250717162547.94582-1-Alexander@wetzel-home.de. ] Signed-off-by: Alva Lan alvalan9@foxmail.com --- net/wireless/reg.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/wireless/reg.c b/net/wireless/reg.c index f6846eb0f4b8..9f8428dc418a 100644 --- a/net/wireless/reg.c +++ b/net/wireless/reg.c @@ -4234,6 +4234,8 @@ static void cfg80211_check_and_end_cac(struct cfg80211_registered_device *rdev) struct wireless_dev *wdev; unsigned int link_id;
+ wiphy_lock(&rdev->wiphy); + /* If we finished CAC or received radar, we should end any * CAC running on the same channels. * the check !cfg80211_chandef_dfs_usable contain 2 options: @@ -4258,6 +4260,8 @@ static void cfg80211_check_and_end_cac(struct cfg80211_registered_device *rdev) rdev_end_cac(rdev, wdev->netdev, link_id); } } + + wiphy_unlock(&rdev->wiphy); }
void regulatory_propagate_dfs_state(struct wiphy *wiphy,