On Wed, Dec 21, 2011 at 02:08:48PM +0100, Oleg Nesterov wrote:
> On 12/21, Frederic Weisbecker wrote:
> > Hi,
> >
> > Starring at some parts of cgroups, I have a few questions:
> >
> > - Is cgroup_enable_task_cg_list()'s while_each_thread() safe
> > against concurrent exec()? The leader may change in de_thread()
> > and invalidate the test done in while_each_thread().
>
> Yes. Oh, we need to do something with while_each_thread.
Would something like this work?
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c0c5876..e002a00 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2293,8 +2293,12 @@ extern bool current_is_single_threaded(void);
#define do_each_thread(g, t) \
for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
-#define while_each_thread(g, t) \
- while ((t = next_thread(t)) != g)
+#define while_each_thread(g, t) \
+ while (({ \
+ struct task_struct *__prev = t; \
+ t = next_thread(t); \
+ t != __prev && t != g; \
+ }))
static inline int get_nr_threads(struct task_struct *tsk)
{
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/containers
