Now everything is ready to pass PIDFD_STALE to pidfd_prepare().
This will allow opening pidfd for reaped tasks.

Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Luca Boccassi <bluca@debian.org>
Cc: David Rheinsberg <david@readahead.eu>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
---
 include/net/scm.h | 1 +
 net/core/scm.c    | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/net/scm.h b/include/net/scm.h
index d1ae0704f230..1960c2b4f0b1 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -8,6 +8,7 @@
 #include <linux/file.h>
 #include <linux/security.h>
 #include <linux/pid.h>
+#include <uapi/linux/pidfd.h>
 #include <linux/pidfs.h>
 #include <linux/nsproxy.h>
 #include <linux/sched/signal.h>
diff --git a/net/core/scm.c b/net/core/scm.c
index 0e71d5a249a1..022d5035d146 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -464,7 +464,7 @@ static void scm_pidfd_recv(struct msghdr *msg, struct scm_cookie *scm)
 	if (!scm->pid)
 		return;
 
-	pidfd = pidfd_prepare(scm->pid, 0, &pidfd_file);
+	pidfd = pidfd_prepare(scm->pid, PIDFD_STALE, &pidfd_file);
 
 	if (put_cmsg(msg, SOL_SOCKET, SCM_PIDFD, sizeof(int), &pidfd)) {
 		if (pidfd_file) {
-- 
2.43.0