Don't release and acquire Giant in mi_switch(). Instead, release and

acquire Giant as needed in functions that call mi_switch().  The releases
need to be done outside of the sched_lock to avoid potential deadlocks
from trying to acquire Giant while interrupts are disabled.

Submitted by:	witness

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c
index 431f966..025ed04 100644
--- a/sys/kern/kern_shutdown.c
+++ b/sys/kern/kern_shutdown.c
@@ -254,6 +254,7 @@ boot(int howto)
 			pbusy = nbusy;
 			sync(&proc0, NULL);
  			if (curproc != NULL) {
+				DROP_GIANT_NOSWITCH();
    				for (subiter = 0; subiter < 50 * iter; subiter++) {
      					mtx_enter(&sched_lock, MTX_SPIN);
      					setrunqueue(curproc);
@@ -261,6 +262,7 @@ boot(int howto)
      					mtx_exit(&sched_lock, MTX_SPIN);
      					DELAY(1000);
    				}
+				PICKUP_GIANT();
  			} else
 			DELAY(50000 * iter);
 		}