sys_prctl(): fix return of uninitialized value

If none of the switch cases match, the PR_SET_PDEATHSIG and
PR_SET_DUMPABLE cases of the switch statement will never write to local
variable `error'.

Signed-off-by: Shi Weihua <shiwh@cn.fujitsu.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Acked-by: "Serge E. Hallyn" <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/sys.c

@@ -1652,7 +1652,7 @@ asmlinkage long sys_umask(int mask)
 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
 			  unsigned long arg4, unsigned long arg5)
 {
-	long uninitialized_var(error);
+	long error = 0;
 
 	if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
 		return error;
@@ -1701,9 +1701,7 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
 			error = PR_TIMING_STATISTICAL;
 			break;
 		case PR_SET_TIMING:
-			if (arg2 == PR_TIMING_STATISTICAL)
-				error = 0;
-			else
+			if (arg2 != PR_TIMING_STATISTICAL)
 				error = -EINVAL;
 			break;