From: Christian Brauner <christian@brauner.io>
To: mtk.manpages@gmail.com
Cc: adrian@lisas.de, akpm@linux-foundation.org, arnd@arndb.de,
avagin@gmail.com, christian.brauner@ubuntu.com,
dhowells@redhat.com, fweimer@redhat.com, jannh@google.com,
keescook@chromium.org, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-man@vger.kernel.org,
mingo@elte.hu, oleg@redhat.com, xemul@virtuozzo.com
Subject: [PATCH] clone.2: Mention that CLONE_PARENT is off-limits for inits
Date: Wed, 20 Nov 2019 11:45:04 +0100 [thread overview]
Message-ID: <20191120104504.22411-1-christian@brauner.io> (raw)
From: Christian Brauner <christian.brauner@ubuntu.com>
The CLONE_PARENT flag cannot but used by init processes. Let's mention
this in the manpages to prevent suprises.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
man2/clone.2 | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/man2/clone.2 b/man2/clone.2
index f0f29d6f1..aa98ab79b 100644
--- a/man2/clone.2
+++ b/man2/clone.2
@@ -646,6 +646,13 @@ if
.B CLONE_PARENT
is set, then the parent of the calling process, rather than the
calling process itself, will be signaled.
+.IP
+The kernel will not allow global init and init processes in pid
+namespaces to use the
+.B CLONE_PARENT
+flag. This is done to prevent the creation of multi-rooted process
+trees. It also avoids unreapable zombies in the initial pid
+namespace.
.TP
.BR CLONE_PARENT_SETTID " (since Linux 2.5.49)"
Store the child thread ID at the location pointed to by
--
2.24.0
next reply other threads:[~2019-11-20 10:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-20 10:45 Christian Brauner [this message]
2019-11-21 9:53 ` [PATCH] clone.2: Mention that CLONE_PARENT is off-limits for inits Michael Kerrisk (man-pages)
2019-11-21 11:27 ` Christian Brauner
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