From 2e13ba54a2682eea24918b87ad3edf70c2cf085b Mon Sep 17 00:00:00 2001 From: Iago López Galeiras Date: Thu, 25 Jun 2015 15:00:57 -0700 Subject: fs, proc: introduce CONFIG_PROC_CHILDREN MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 818411616baf ("fs, proc: introduce /proc//task//children entry") introduced the children entry for checkpoint restore and the file is only available on kernels configured with CONFIG_EXPERT and CONFIG_CHECKPOINT_RESTORE. This is available in most distributions (Fedora, Debian, Ubuntu, CoreOS) because they usually enable CONFIG_EXPERT and CONFIG_CHECKPOINT_RESTORE. But Arch does not enable CONFIG_EXPERT or CONFIG_CHECKPOINT_RESTORE. However, the children proc file is useful outside of checkpoint restore. I would like to use it in rkt. The rkt process exec() another program it does not control, and that other program will fork()+exec() a child process. I would like to find the pid of the child process from an external tool without iterating in /proc over all processes to find which one has a parent pid equal to rkt. This commit introduces CONFIG_PROC_CHILDREN and makes CONFIG_CHECKPOINT_RESTORE select it. This allows enabling /proc//task//children without needing to enable CONFIG_CHECKPOINT_RESTORE and CONFIG_EXPERT. Alban tested that /proc//task//children is present when the kernel is configured with CONFIG_PROC_CHILDREN=y but without CONFIG_CHECKPOINT_RESTORE Signed-off-by: Iago López Galeiras Tested-by: Alban Crequy Reviewed-by: Cyrill Gorcunov Cc: Oleg Nesterov Cc: Kees Cook Cc: Pavel Emelyanov Cc: Serge Hallyn Cc: KAMEZAWA Hiroyuki Cc: Alexander Viro Cc: Andy Lutomirski Cc: Djalal Harouni Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index b999fa381bf9..6a930b7494ef 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1131,6 +1131,7 @@ endif # CGROUPS config CHECKPOINT_RESTORE bool "Checkpoint/restore support" if EXPERT + select PROC_CHILDREN default n help Enables additional kernel features in a sake of checkpoint/restore. -- cgit v1.2.3