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Commit 3f5e554f authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge
Browse files

xen/evtchn: don't do unbind_from_irqhandler under spinlock 



unbind_from_irqhandler can end up doing /proc operations, which can't
happen under a spinlock.  So before removing the IRQ handler,
disable the irq under the port_user lock (masking the underlying event
channel and making sure the irq handler isn't running concurrently and
won't start running), then remove the handler without the lock.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
parent 1a1a17cd

drivers/xen/evtchn.c

+11 −2
Original line number Diff line number Diff line
@@ -375,10 +375,12 @@ static long evtchn_ioctl(struct file *file, 
			break;

		}



		evtchn_unbind_from_user(u, unbind.port);

		disable_irq(irq_from_evtchn(unbind.port));



		spin_unlock_irq(&port_user_lock);



		evtchn_unbind_from_user(u, unbind.port);



		rc = 0;

		break;

	}
@@ -484,11 +486,18 @@ static int evtchn_release(struct inode *inode, struct file *filp) 
		if (get_port_user(i) != u)

			continue;



		evtchn_unbind_from_user(get_port_user(i), i);

		disable_irq(irq_from_evtchn(i));

	}



	spin_unlock_irq(&port_user_lock);



	for (i = 0; i < NR_EVENT_CHANNELS; i++) {

		if (get_port_user(i) != u)

			continue;



		evtchn_unbind_from_user(get_port_user(i), i);

	}



	kfree(u->name);

	kfree(u);