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-rw-r--r--mm/util.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c
index 136ac4f..ae962b3 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -239,6 +239,47 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
next->vm_prev = vma;
}
+/* Check if the vma is being used as a stack by this task */
+static int vm_is_stack_for_task(struct task_struct *t,
+ struct vm_area_struct *vma)
+{
+ return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
+}
+
+/*
+ * Check if the vma is being used as a stack.
+ * If is_group is non-zero, check in the entire thread group or else
+ * just check in the current task. Returns the pid of the task that
+ * the vma is stack for.
+ */
+pid_t vm_is_stack(struct task_struct *task,
+ struct vm_area_struct *vma, int in_group)
+{
+ pid_t ret = 0;
+
+ if (vm_is_stack_for_task(task, vma))
+ return task->pid;
+
+ if (in_group) {
+ struct task_struct *t;
+ rcu_read_lock();
+ if (!pid_alive(task))
+ goto done;
+
+ t = task;
+ do {
+ if (vm_is_stack_for_task(t, vma)) {
+ ret = t->pid;
+ goto done;
+ }
+ } while_each_thread(task, t);
+done:
+ rcu_read_unlock();
+ }
+
+ return ret;
+}
+
#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
void arch_pick_mmap_layout(struct mm_struct *mm)
{
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