From 3f5e554f669098c84c82ce75e7577f7e0f3fccde Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Fri, 28 May 2010 15:28:27 -0700 Subject: [PATCH] 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: Jeremy Fitzhardinge --- drivers/xen/evtchn.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c index f79ac5ca3793..6a3a12945d02 100644 --- a/drivers/xen/evtchn.c +++ b/drivers/xen/evtchn.c @@ -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); -- 2.20.1