drivers: usb: host: Fix deadlock in oxu_bus_suspend()

stable inclusion
from stable-v5.10.122
commit ffe9440d698274c6462d2e304562c6ddfc8c84df
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5W6OE

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ffe9440d698274c6462d2e304562c6ddfc8c84df

--------------------------------

[ Upstream commit 4d378f2a ]

There is a deadlock in oxu_bus_suspend(), which is shown below:

   (Thread 1)              |      (Thread 2)
                           | timer_action()
oxu_bus_suspend()          |  mod_timer()
 spin_lock_irq() //(1)     |  (wait a time)
 ...                       | oxu_watchdog()
 del_timer_sync()          |  spin_lock_irq() //(2)
 (wait timer to stop)      |  ...

We hold oxu->lock in position (1) of thread 1, and use
del_timer_sync() to wait timer to stop, but timer handler
also need oxu->lock in position (2) of thread 2. As a result,
oxu_bus_suspend() will block forever.

This patch extracts del_timer_sync() from the protection of
spin_lock_irq(), which could let timer handler to obtain
the needed lock.
Signed-off-by: NDuoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220417120305.64577-1-duoming@zju.edu.cnSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

drivers/usb/host/oxu210hp-hcd.c

@@ -3908,8 +3908,10 @@ static int oxu_bus_suspend(struct usb_hcd *hcd)
 		}
 	}
 
+	spin_unlock_irq(&oxu->lock);
 	/* turn off now-idle HC */
 	del_timer_sync(&oxu->watchdog);
+	spin_lock_irq(&oxu->lock);
 	ehci_halt(oxu);
 	hcd->state = HC_STATE_SUSPENDED;