• Serge E. Hallyn's avatar
    pid namespaces: define is_global_init() and is_container_init() · b460cbc5
    Serge E. Hallyn authored
    is_init() is an ambiguous name for the pid==1 check.  Split it into
    is_global_init() and is_container_init().
    A cgroup init has it's tsk->pid == 1.
    A global init also has it's tsk->pid == 1 and it's active pid namespace
    is the init_pid_ns.  But rather than check the active pid namespace,
    compare the task structure with 'init_pid_ns.child_reaper', which is
    initialized during boot to the /sbin/init process and never changes.
    	- Use 'init_pid_ns.child_reaper' to determine if a given task is the
    	  global init (/sbin/init) process. This would improve performance
    	  and remove dependence on the task_pid().
    	- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
    	  ppc,avr32}/traps.c for the _exception() call to is_global_init().
    	  This way, we kill only the cgroup if the cgroup's init has a
    	  bug rather than force a kernel panic.
    [akpm@linux-foundation.org: fix comment]
    [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
    [bunk@stusta.de: kernel/pid.c: remove unused exports]
    [sukadev@us.ibm.com: Fix capability.c to work with threaded init]
    Signed-off-by: default avatarSerge E. Hallyn <serue@us.ibm.com>
    Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@us.ibm.com>
    Acked-by: default avatarPavel Emelianov <xemul@openvz.org>
    Cc: Eric W. Biederman <ebiederm@xmission.com>
    Cc: Cedric Le Goater <clg@fr.ibm.com>
    Cc: Dave Hansen <haveblue@us.ibm.com>
    Cc: Herbert Poetzel <herbert@13thfloor.at>
    Cc: Kirill Korotaev <dev@sw.ru>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>