Move a vref call outside of proc locks and Giant. By virtue of the fact

that we (p1) are currently running, we hold a reference on p_textvp which
means the vnode cannot go away.  p2 cannot run yet (and hence cannot exit)
so this should be safe to do at this point.  As a bonus, it removes a
block of under-Giant code that was there to support the vref.

1 files changed, 4 insertions, 5 deletions

diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 1c39c42..34a1bfd 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -474,7 +474,6 @@ again:
 	if (pages != 0)
 		vm_thread_new_altkstack(td2, pages);
 
-	mtx_lock(&Giant);	/* XXX: for VREF() */
 	PROC_LOCK(p2);
 	PROC_LOCK(p1);
 
@@ -537,11 +536,7 @@ again:
 	else
 	        p2->p_sigparent = SIGCHLD;
 
-	/* Bump references to the text vnode (for procfs) */
 	p2->p_textvp = p1->p_textvp;
-	if (p2->p_textvp)
-		VREF(p2->p_textvp);
-	mtx_unlock(&Giant); /* XXX: for VREF() */
 	p2->p_fd = fd;
 	p2->p_fdtol = fdtol;
 
@@ -552,6 +547,10 @@ again:
 	PROC_UNLOCK(p1);
 	PROC_UNLOCK(p2);
 
+	/* Bump references to the text vnode (for procfs) */
+	if (p2->p_textvp)
+		vref(p2->p_textvp);
+
 	/*
 	 * Set up linkage for kernel based threading.
 	 */