[PATCH] usb: hcd: queue wakeup_work to system_freezable_wq workqueue

[Xu Yang]

After commit 4fb352df14de ("PM: sleep: Do not flag runtime PM workqueue
as freezable"), pm_wq workqueue will be unfreezable during system pm. This
brings issue as below:

[  344.255749] ------------[ cut here ]------------
[  344.277740] URB 000000004aae4ad1 submitted while active
[  344.282996] WARNING: drivers/usb/core/urb.c:379 at usb_submit_urb+0x5a4/0x5e0, CPU#2: kworker/u16:14/964
[  344.292477] Modules linked in:
[  344.295532] CPU: 2 UID: 0 PID: 964 Comm: kworker/u16:14 Not tainted 7.0.0-rc2-next-20260303-00006-gf03fe0b53b39-dirty #100 PREEMPT
[  344.307341] Hardware name: NXP i.MX943 EVK board (DT)
[  344.312386] Workqueue: async async_run_entry_fn
[  344.316919] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  344.323862] pc : usb_submit_urb+0x5a4/0x5e0
[  344.328046] lr : usb_submit_urb+0x5a4/0x5e0
[  344.332217] sp : ffff800083283b30
[  344.335528] x29: ffff800083283b30 x28: ffff000082631000 x27: 0000000000000000
[  344.342661] x26: 0000000000000003 x25: 0000000000000c00 x24: 0000000000000000
[  344.349793] x23: 0000000000000004 x22: 0000000000000010 x21: 0000000000000000
[  344.356917] x20: 0000000000000002 x19: ffff00008253ce40 x18: ffff000089e4eec0
[  344.364050] x17: 000000040044ffff x16: 000005d9d87f6289 x15: 0000000000000000
[  344.371174] x14: ffff000089e4eec0 x13: 6576697463612065 x12: 6c69687720646574
[  344.378298] x11: 0000000000000058 x10: 0000000000000001 x9 : 0000000000000001
[  344.385431] x8 : 0000000000000000 x7 : 0000005028dd0800 x6 : 0000000000000002
[  344.392563] x5 : ffffc48f74e9daf8 x4 : 0000000000000000 x3 : 0000000000000000
[  344.399696] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000089e4ee40
[  344.406835] Call trace:
[  344.409280]  usb_submit_urb+0x5a4/0x5e0 (P)
[  344.413456]  hub_activate+0x268/0x878
[  344.417116]  hub_resume+0x5c/0x10c
[  344.420522]  usb_resume_interface.isra.0+0xa8/0x110
[  344.425393]  usb_resume_both+0x10c/0x1e0
[  344.429310]  usb_resume+0x1c/0x70
[  344.432621]  usb_dev_resume+0x14/0x20
[  344.436278]  dpm_run_callback.isra.0+0x38/0xf8
[  344.440715]  device_resume+0xec/0x1e8
[  344.444373]  async_resume+0x20/0x38
[  344.447848]  async_run_entry_fn+0x34/0xe0
[  344.451852]  process_one_work+0x150/0x290
[  344.455856]  worker_thread+0x18c/0x300
[  344.459600]  kthread+0x118/0x124
[  344.462824]  ret_from_fork+0x10/0x20

The reason is if the host controller resume routine xhci_resume() call
usb_hcd_resume_root_hub(), wakeup_work will be queued and run immediately.
Then usb_autoresume_device() will be called and usb device will exit
runtime suspended state (if it was suspended before). For a hub device,
hub_resume()/hub_reset_resume() will be called accordingly.

After the host controller device system resume is finished, the root hub
usb device "usb1" will do system resume too. Then hub_resume() will be
called again.

Above sequence will cause hub->urb to be submitted twice. To avoid this
issue, restore the previous behavior by queuing wakeup_work to
system_freezable_wq workqueue.

Fixes: 4fb352df14de ("PM: sleep: Do not flag runtime PM workqueue as freezable")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
---
 drivers/usb/core/hcd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index dee842ea6931..89221f1ce769 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2403,7 +2403,7 @@ void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
 	if (hcd->rh_registered) {
 		pm_wakeup_event(&hcd->self.root_hub->dev, 0);
 		set_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
-		queue_work(pm_wq, &hcd->wakeup_work);
+		queue_work(system_freezable_wq, &hcd->wakeup_work);
 	}
 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
 }
-- 
2.34.1