linux-toradex.git/kernel/pid_namespace.c, branch tegra-9.12.14

pidns: deny CLONE_PARENT|CLONE_NEWPID combination

2009-09-24T14:21:04+00:00

CLONE_PARENT was used to implement an older threading model.  For
consistency with the CLONE_THREAD check in copy_pid_ns(), disable
CLONE_PARENT with CLONE_NEWPID, at least until the required semantics of
pid namespaces are clear.

Signed-off-by: Sukadev Bhattiprolu 
Acked-by: Roland McGrath 
Acked-by: Serge Hallyn 
Cc: Oren Laadan 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pidns: rewrite copy_pid_ns()

2009-06-18T20:03:55+00:00

copy_pid_ns() is a perfect example of a case where unwinding leads to more
code and makes it less clear.  Watch the diffstat.

Signed-off-by: Alexey Dobriyan 
Cc: Pavel Emelyanov 
Cc: "Eric W. Biederman" 
Reviewed-by: Serge Hallyn 
Acked-by: Sukadev Bhattiprolu 
Reviewed-by: WANG Cong 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pidns: make create_pid_namespace() accept parent pidns

2009-06-18T20:03:55+00:00

create_pid_namespace() creates everything, but caller has to assign parent
pidns by hand, which is unnatural.  At the moment of call new ->level has
to be taken from somewhere and parent pidns is already available.

Signed-off-by: Alexey Dobriyan 
Cc: Pavel Emelyanov 
Cc: "Eric W. Biederman" 
Acked-by: Serge Hallyn 
Acked-by: Sukadev Bhattiprolu 
Reviewed-by: WANG Cong 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

signals: zap_pid_ns_process() should use force_sig()

2009-04-03T02:04:58+00:00

send_signal() assumes that signals with SEND_SIG_PRIV are generated from
within the same namespace.  So any nested container-init processes become
immune to the SIGKILL generated by kill_proc_info() in
zap_pid_ns_processes().

Use force_sig() in zap_pid_ns_processes() instead - force_sig() clears the
SIGNAL_UNKILLABLE flag ensuring the signal is processed by
container-inits.

Signed-off-by: Sukadev Bhattiprolu 
Cc: Oleg Nesterov 
Cc: Roland McGrath 
Cc: "Eric W. Biederman" 
Cc: Daniel Lezcano 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exits

2008-09-03T02:21:38+00:00

We don't change pid_ns->child_reaper when the main thread of the
subnamespace init exits.  As Robert Rex  pointed
out this is wrong.

Yes, the re-parenting itself works correctly, but if the reparented task
exits it needs ->parent->nsproxy->pid_ns in do_notify_parent(), and if the
main thread is zombie its ->nsproxy was already cleared by
exit_task_namespaces().

Introduce the new function, find_new_reaper(), which finds the new
->parent for the re-parenting and changes ->child_reaper if needed.  Kill
the now unneeded exit_child_reaper().

Also move the changing of ->child_reaper from zap_pid_ns_processes() to
find_new_reaper(), this consolidates the games with ->child_reaper and
makes it stable under tasklist_lock.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11391

Reported-by: Robert Rex 
Signed-off-by: Oleg Nesterov 
Acked-by: Serge Hallyn 
Acked-by: Pavel Emelyanov 
Acked-by: Sukadev Bhattiprolu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid_ns: zap_pid_ns_processes: fix the ->child_reaper changing

2008-09-03T02:21:38+00:00

zap_pid_ns_processes() sets pid_ns->child_reaper = NULL, this is wrong.

Yes, we have already killed all tasks in this namespace, and sys_wait4()
doesn't see any child.  But this doesn't mean ->children list is empty, we
may have EXIT_DEAD tasks which are not visible to do_wait().  In that case
the subsequent forget_original_parent() will crash the kernel because it
will try to re-parent these tasks to the NULL reaper.

Even if there are no childs, it is not good that forget_original_parent()
uses reaper == NULL.

Change the code to set ->child_reaper = init_pid_ns.child_reaper instead.
We could use pid_ns->parent->child_reaper as well, I think this does not
really matter.  These EXIT_DEAD tasks are not visible to the new ->parent
after re-parenting, they will silently do release_task() eventually.

Note that we must change ->child_reaper, otherwise
forget_original_parent() will use reaper == father, and in that case we
will hit the (correct) BUG_ON(!list_empty(&father->children)).

Signed-off-by: Oleg Nesterov 
Acked-by: Serge Hallyn 
Acked-by: Sukadev Bhattiprolu 
Acked-by: Pavel Emelyanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bsdacct: switch from global bsd_acct_struct instance to per-pidns one

2008-07-25T17:53:47+00:00

Allocate the structure on the first call to sys_acct().  After this each
namespace, that ordered the accounting, will live with this structure till
its own death.

Two notes
- routines, that close the accounting on fs umount time use
  the init_pid_ns's acct by now;
- accounting routine accounts to dying task's namespace
  (also by now).

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pidns: use kzalloc when allocating new pid_namespace struct

2008-07-25T17:53:46+00:00

It makes many fields initialization implicit helping in auto-setting
#ifdef-ed fields (bsd-acct related pointer will be such).

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pidns: make pid->level and pid_ns->level unsigned

2008-04-30T15:29:49+00:00

These values represent the nesting level of a namespace and pids living in it,
and it's always non-negative.

Turning this from int to unsigned int saves some space in pid.c (11 bytes on
x86 and 64 on ia64) by letting the compiler optimize the pid_nr_ns a bit.
E.g.  on ia64 this removes the sign extension calls, which compiler adds to
optimize access to pid->nubers[ns->level].

Signed-off-by: Pavel Emelyanov 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel: fix integer as NULL pointer warnings

2008-04-29T00:29:18+00:00

kernel/cpuset.c:1268:52: warning: Using plain integer as NULL pointer
kernel/pid_namespace.c:95:24: warning: Using plain integer as NULL pointer

Signed-off-by: Harvey Harrison 
Reviewed-by: Paul Jackson 
Signed-off-by: Linus Torvalds