USB: fix locking loop by avoiding flush_scheduled_work

This patch (as1027) replaces a call to flush_scheduled_work() -- a
dangerous routine to invoke, especially while holding any sort of lock
-- with calls to cancel_work_sync() and cancel_delayed_work_sync().

This fixes Bugzilla #9532.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 13b326a..b04d232 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -522,9 +522,9 @@ static void hub_quiesce(struct usb_hub *hub)
        /* (blocking) stop khubd and related activity */
        usb_kill_urb(hub->urb);
        if (hub->has_indicators)
-               cancel_delayed_work(&hub->leds);
-       if (hub->has_indicators || hub->tt.hub)
-               flush_scheduled_work();
+               cancel_delayed_work_sync(&hub->leds);
+       if (hub->tt.hub)
+               cancel_work_sync(&hub->tt.kevent);
 }
 
 static void hub_activate(struct usb_hub *hub)