Old bug.
# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
# 2005/04/22 15:19:02-07:00 kmacy@curly.lab.netapp.com
# Fix lockup in evtchn_do_upcall
# Signed-off-by: Kip Macy <kmacy@fsmware.com>
#
# freebsd-5.3-xen-sparse/i386-xen/i386-xen/evtchn.c
# 2005/04/22 15:18:57-07:00 kmacy@curly.lab.netapp.com +6 -1
# Work around potential recursive locking in event channel handler
#
diff -Nru a/freebsd-5.3-xen-sparse/i386-xen/i386-xen/evtchn.c
b/freebsd-5.3-xen-sparse/i386-xen/i386-xen/e
vtchn.c
--- a/freebsd-5.3-xen-sparse/i386-xen/i386-xen/evtchn.c 2005-04-21
15:24:19 -07:00
+++ b/freebsd-5.3-xen-sparse/i386-xen/i386-xen/evtchn.c 2005-04-21
15:24:19 -07:00
@@ -54,7 +54,7 @@
{
unsigned long l1, l2;
unsigned int l1i, l2i, port;
- int irq;
+ int irq, owned;
unsigned long flags;
shared_info_t *s = HYPERVISOR_shared_info;
vcpu_info_t *vcpu_info = &s->vcpu_data[smp_processor_id()];
@@ -78,12 +78,17 @@
l2 &= ~(1 << l2i);
port = (l1i << 5) + l2i;
+ if ((owned = mtx_owned(&sched_lock)) != 0)
+ mtx_unlock_spin_flags(&sched_lock, MTX_QUIET);
if ( (irq = evtchn_to_irq[port]) != -1 ) {
struct intsrc *isrc = intr_lookup_source(irq);
intr_execute_handlers(isrc, frame);
} else {
evtchn_device_upcall(port);
}
+ if (owned)
+ mtx_lock_spin_flags(&sched_lock, MTX_QUIET);
+
}
}
}
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