From fdbaa60278d99ae90b16185ad58f959230b3a0fe Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Fri, 25 Apr 2003 19:52:30 +0000
Subject: [PATCH] Lock Giant around calls to useracc() in osf1_sigreturn() so
 that the function is MP safe.

---
 sys/alpha/osf1/osf1_signal.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sys/alpha/osf1/osf1_signal.c b/sys/alpha/osf1/osf1_signal.c
index d2ecd39d1e92..3f03ef173718 100644
--- a/sys/alpha/osf1/osf1_signal.c
+++ b/sys/alpha/osf1/osf1_signal.c
@@ -572,6 +572,7 @@ osf1_sigreturn(struct thread *td,
 
 	p = td->td_proc;
 	scp = uap->sigcntxp;
+	mtx_lock(&Giant);
 	if (useracc((caddr_t)scp, sizeof (*scp), VM_PROT_READ) == 0 ) {
 		uprintf("uac fails\n");
 		uprintf("scp: %p\n", scp);
@@ -581,8 +582,11 @@ osf1_sigreturn(struct thread *td,
 	 * We grab it all at once for speed.
 	 */
 	if (useracc((caddr_t)scp, sizeof (*scp), VM_PROT_READ) == 0 ||
-	    copyin((caddr_t)scp, (caddr_t)&ksc, sizeof ksc))
+	    copyin((caddr_t)scp, (caddr_t)&ksc, sizeof ksc)) {
+		mtx_unlock(&Giant);
 		return (EFAULT);
+	}
+	mtx_unlock(&Giant);
 
 	/*
 	 * Restore the user-supplied information.