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-rw-r--r--kernel/exit.c21
1 files changed, 7 insertions, 14 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index e69edc74aeeb..2a803c28df9e 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -642,35 +642,31 @@ retry:
/*
* We found no owner yet mm_users > 1: this implies that we are
* most likely racing with swapoff (try_to_unuse()) or /proc or
- * ptrace or page migration (get_task_mm()). Mark owner as NULL,
- * so that subsystems can understand the callback and take action.
+ * ptrace or page migration (get_task_mm()). Mark owner as NULL.
*/
- down_write(&mm->mmap_sem);
- cgroup_mm_owner_callbacks(mm->owner, NULL);
mm->owner = NULL;
- up_write(&mm->mmap_sem);
return;
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 */
@@ -1052,10 +1048,7 @@ NORET_TYPE void do_exit(long code)
preempt_count());
acct_update_integrals(tsk);
- if (tsk->mm) {
- update_hiwater_rss(tsk->mm);
- update_hiwater_vm(tsk->mm);
- }
+
group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) {
hrtimer_cancel(&tsk->signal->real_timer);