kernel/signal.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index dfcee3888b00..f58f1d574931 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -4161,7 +4161,6 @@ do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
 		size_t min_ss_size)
 {
 	struct task_struct *t = current;
-	int ret = 0;
 
 	if (oss) {
 		memset(oss, 0, sizeof(stack_t));
@@ -4181,8 +4180,15 @@ do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
 			return -EPERM;
 
 		ss_mode = ss_flags & ~SS_FLAG_BITS;
-		if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
-				ss_mode != 0))
+
+		if (ss_mode == SS_DISABLE) {
+			t->sas_ss_sp = 0;
+			t->sas_ss_size = 0;
+			t->sas_ss_flags = ss_flags;
+			return 0;
+		}
+
+		if (unlikely(ss_mode != SS_ONSTACK && ss_mode != 0))
 			return -EINVAL;
 
 		/*
@@ -4194,24 +4200,20 @@ do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
 		    t->sas_ss_flags == ss_flags)
 			return 0;
 
+		/* Is this lock really worth it? */
 		sigaltstack_lock();
-		if (ss_mode == SS_DISABLE) {
-			ss_size = 0;
-			ss_sp = NULL;
-		} else {
-			if (unlikely(ss_size < min_ss_size))
-				ret = -ENOMEM;
-			if (!sigaltstack_size_valid(ss_size))
-				ret = -ENOMEM;
-		}
-		if (!ret) {
-			t->sas_ss_sp = (unsigned long) ss_sp;
-			t->sas_ss_size = ss_size;
-			t->sas_ss_flags = ss_flags;
+		if (unlikely(ss_size < min_ss_size) ||
+		    unlikely(sigaltstack_size_valid(ss_size))) {
+			sigaltstack_unlock();
+			return -ENOMEM;
 		}
 		sigaltstack_unlock();
+
+		t->sas_ss_sp = (unsigned long) ss_sp;
+		t->sas_ss_size = ss_size;
+		t->sas_ss_flags = ss_flags;
 	}
-	return ret;
+	return 0;
 }
 
 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)