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| author | Iago López Galeiras <iago@endocode.com> | 2015-06-26 00:00:57 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-26 02:00:37 +0200 |
| commit | 2e13ba54a2682eea24918b87ad3edf70c2cf085b (patch) | |
| tree | faa1c51d66968fada40fc971c3c17d1a242c7857 /init | |
| parent | proc: fix PAGE_SIZE limit of /proc/$PID/cmdline (diff) | |
| download | linux-2e13ba54a2682eea24918b87ad3edf70c2cf085b.tar.xz linux-2e13ba54a2682eea24918b87ad3edf70c2cf085b.zip | |
fs, proc: introduce CONFIG_PROC_CHILDREN
Commit 818411616baf ("fs, proc: introduce /proc/<pid>/task/<tid>/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/<pid>/task/<tid>/children without needing to enable
CONFIG_CHECKPOINT_RESTORE and CONFIG_EXPERT.
Alban tested that /proc/<pid>/task/<tid>/children is present when the
kernel is configured with CONFIG_PROC_CHILDREN=y but without
CONFIG_CHECKPOINT_RESTORE
Signed-off-by: Iago López Galeiras <iago@endocode.com>
Tested-by: Alban Crequy <alban@endocode.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Djalal Harouni <djalal@endocode.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
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. |