From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 30 Sep 2013 20:45:27 +0000 (-0700)
Subject: pidns: fix free_pid() to handle the first fork failure
X-Git-Tag: v5.15~19220^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=314a8ad0f18ac37887896b288939acd8cb17e208;p=platform%2Fkernel%2Flinux-starfive.git

pidns: fix free_pid() to handle the first fork failure

"case 0" in free_pid() assumes that disable_pid_allocation() should
clear PIDNS_HASH_ADDING before the last pid goes away.

However this doesn't happen if the first fork() fails to create the
child reaper which should call disable_pid_allocation().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/pid.c b/kernel/pid.c
index ebe5e80..9b9a266 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -273,6 +273,11 @@ void free_pid(struct pid *pid)
 			 */
 			wake_up_process(ns->child_reaper);
 			break;
+		case PIDNS_HASH_ADDING:
+			/* Handle a fork failure of the first process */
+			WARN_ON(ns->child_reaper);
+			ns->nr_hashed = 0;
+			/* fall through */
 		case 0:
 			schedule_work(&ns->proc_work);
 			break;