diff options
| -rw-r--r-- | include/linux/cgroup.h | 3 | ||||
| -rw-r--r-- | kernel/cgroup.c | 4 | ||||
| -rw-r--r-- | kernel/exit.c | 9 |
3 files changed, 9 insertions, 7 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c98dd7cb707..30934e4bfaa 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -326,7 +326,8 @@ struct cgroup_subsys { */ void (*mm_owner_changed)(struct cgroup_subsys *ss, struct cgroup *old, - struct cgroup *new); + struct cgroup *new, + struct task_struct *p); int subsys_id; int active; int disabled; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index a0123d75ec9..8c6e1c17e6d 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2735,6 +2735,8 @@ void cgroup_fork_callbacks(struct task_struct *child) * Called on every change to mm->owner. mm_init_owner() does not * invoke this routine, since it assigns the mm->owner the first time * and does not change it. + * + * The callbacks are invoked with mmap_sem held in read mode. */ void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new) { @@ -2750,7 +2752,7 @@ void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new) if (oldcgrp == newcgrp) continue; if (ss->mm_owner_changed) - ss->mm_owner_changed(ss, oldcgrp, newcgrp); + ss->mm_owner_changed(ss, oldcgrp, newcgrp, new); } } } diff --git a/kernel/exit.c b/kernel/exit.c index 85a83c83185..0ef4673e351 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -640,24 +640,23 @@ retry: assign_new_owner: BUG_ON(c == p); get_task_struct(c); + read_unlock(&tasklist_lock); + down_write(&mm->mmap_sem); /* * The task_lock protects c->mm from changing. * We always want mm->owner->mm == mm */ task_lock(c); - /* - * Delay read_unlock() till we have the task_lock() - * to ensure that c does not slip away underneath us - */ - read_unlock(&tasklist_lock); if (c->mm != mm) { task_unlock(c); + up_write(&mm->mmap_sem); put_task_struct(c); goto retry; } cgroup_mm_owner_callbacks(mm->owner, c); mm->owner = c; task_unlock(c); + up_write(&mm->mmap_sem); put_task_struct(c); } #endif /* CONFIG_MM_OWNER */ |