Lockdep gives a splat [1] when ser_hdl_work item is executed. It is
scheduled at mac80211 workqueue via ieee80211_queue_work() and takes a
wiphy lock inside. However, this workqueue can be flushed when e.g.
closing the interface and wiphy lock is already taken in that case.
Choosing wiphy_work_queue() for SER is likely not suitable. Back on to
the global workqueue.
[1]:
WARNING: possible circular locking dependency detected
6.17.0-rc2 #17 Not tainted
------------------------------------------------------
kworker/u32:1/61 is trying to acquire lock:
ffff88811bc00768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: ser_state_run+0x5e/0x180 [rtw89_core]
but task is already holding lock:
ffffc9000048fd30 ((work_completion)(&ser->ser_hdl_work)){+.+.}-{0:0}, at: process_one_work+0x7b5/0x1450
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 ((work_completion)(&ser->ser_hdl_work)){+.+.}-{0:0}:
process_one_work+0x7c6/0x1450
worker_thread+0x49e/0xd00
kthread+0x313/0x640
ret_from_fork+0x221/0x300
ret_from_fork_asm+0x1a/0x30
-> #1 ((wq_completion)phy0){+.+.}-{0:0}:
touch_wq_lockdep_map+0x8e/0x180
__flush_workqueue+0x129/0x10d0
ieee80211_stop_device+0xa8/0x110
ieee80211_do_stop+0x14ce/0x2880
ieee80211_stop+0x13a/0x2c0
__dev_close_many+0x18f/0x510
__dev_change_flags+0x25f/0x670
netif_change_flags+0x7b/0x160
do_setlink.isra.0+0x1640/0x35d0
rtnl_newlink+0xd8c/0x1d30
rtnetlink_rcv_msg+0x700/0xb80
netlink_rcv_skb+0x11d/0x350
netlink_unicast+0x49a/0x7a0
netlink_sendmsg+0x759/0xc20
____sys_sendmsg+0x812/0xa00
___sys_sendmsg+0xf7/0x180
__sys_sendmsg+0x11f/0x1b0
do_syscall_64+0xbb/0x360
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&rdev->wiphy.mtx){+.+.}-{4:4}:
__lock_acquire+0x124c/0x1d20
lock_acquire+0x154/0x2e0
__mutex_lock+0x17b/0x12f0
ser_state_run+0x5e/0x180 [rtw89_core]
rtw89_ser_hdl_work+0x119/0x220 [rtw89_core]
process_one_work+0x82d/0x1450
worker_thread+0x49e/0xd00
kthread+0x313/0x640
ret_from_fork+0x221/0x300
ret_from_fork_asm+0x1a/0x30
other info that might help us debug this:
Chain exists of:
&rdev->wiphy.mtx --> (wq_completion)phy0 --> (work_completion)(&ser->ser_hdl_work)
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock((work_completion)(&ser->ser_hdl_work));
lock((wq_completion)phy0);
lock((work_completion)(&ser->ser_hdl_work));
lock(&rdev->wiphy.mtx);
*** DEADLOCK ***
2 locks held by kworker/u32:1/61:
#0: ffff888103835148 ((wq_completion)phy0){+.+.}-{0:0}, at: process_one_work+0xefa/0x1450
#1: ffffc9000048fd30 ((work_completion)(&ser->ser_hdl_work)){+.+.}-{0:0}, at: process_one_work+0x7b5/0x1450
stack backtrace:
CPU: 0 UID: 0 PID: 61 Comm: kworker/u32:1 Not tainted 6.17.0-rc2 #17 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS edk2-20250523-14.fc42 05/23/2025
Workqueue: phy0 rtw89_ser_hdl_work [rtw89_core]
Call Trace:
dump_stack_lvl+0x5d/0x80
print_circular_bug.cold+0x178/0x1be
check_noncircular+0x14c/0x170
__lock_acquire+0x124c/0x1d20
lock_acquire+0x154/0x2e0
__mutex_lock+0x17b/0x12f0
ser_state_run+0x5e/0x180 [rtw89_core]
rtw89_ser_hdl_work+0x119/0x220 [rtw89_core]
process_one_work+0x82d/0x1450
worker_thread+0x49e/0xd00
kthread+0x313/0x640
ret_from_fork+0x221/0x300
ret_from_fork_asm+0x1a/0x30
Found by Linux Verification Center (linuxtesting.org).
Fixes: ebfc9199df05 ("wifi: rtw89: add wiphy_lock() to work that isn't held wiphy_lock() yet")
Signed-off-by: Fedor Pchelkin
---
drivers/net/wireless/realtek/rtw89/ser.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtw89/ser.c b/drivers/net/wireless/realtek/rtw89/ser.c
index fe7beff8c424..f99e179f7ff9 100644
--- a/drivers/net/wireless/realtek/rtw89/ser.c
+++ b/drivers/net/wireless/realtek/rtw89/ser.c
@@ -205,7 +205,6 @@ static void rtw89_ser_hdl_work(struct work_struct *work)
static int ser_send_msg(struct rtw89_ser *ser, u8 event)
{
- struct rtw89_dev *rtwdev = container_of(ser, struct rtw89_dev, ser);
struct ser_msg *msg = NULL;
if (test_bit(RTW89_SER_DRV_STOP_RUN, ser->flags))
@@ -221,7 +220,7 @@ static int ser_send_msg(struct rtw89_ser *ser, u8 event)
list_add(&msg->list, &ser->msg_q);
spin_unlock_irq(&ser->msg_q_lock);
- ieee80211_queue_work(rtwdev->hw, &ser->ser_hdl_work);
+ schedule_work(&ser->ser_hdl_work);
return 0;
}
--
2.51.0