6.1-stable review patch. If anyone has any objections, please let me know.
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From: Fedor Pchelkin pchelkin@ispras.ru
[ Upstream commit 570f94511766f9236d3462dfb8a3c719c2b54c23 ]
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: <TASK> 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 </TASK>
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 pchelkin@ispras.ru Acked-by: Ping-Ke Shih pkshih@realtek.com Signed-off-by: Ping-Ke Shih pkshih@realtek.com Link: https://patch.msgid.link/20250919210852.823912-5-pchelkin@ispras.ru Signed-off-by: Sasha Levin sashal@kernel.org --- 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 f5dacdc4d11ab..24a9025e5bea8 100644 --- a/drivers/net/wireless/realtek/rtw89/ser.c +++ b/drivers/net/wireless/realtek/rtw89/ser.c @@ -204,7 +204,6 @@ 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)) @@ -220,7 +219,7 @@ 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; }