[PATCH] sys_waitid: return -EFAULT for NULL

[Roland McGrath <roland@redhat.com>]

It's always been invalid to call waitid() with a NULL pointer.  It was an
oversight that it was allowed (and acts like a wait4() call instead).

Signed-off-by: Roland McGrath <roland@redhat.com>
---
 kernel/exit.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index c7740fa..fa25790 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1760,6 +1760,8 @@ asmlinkage long sys_waitid(int which, pid_t upid,
 	enum pid_type type;
 	long ret;
 
+	if (unlikely(!infop))
+		return -EFAULT;
 	if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
 		return -EINVAL;
 	if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))