From: Zeng Zhaoming <zengzm.kernel@xxxxxxxxx>
find_task_by_vpid should be protected by rcu_read_lock(),
to prevent free_pid() reclaiming pid.
Signed-off-by: Zeng Zhaoming <zengzm.kernel@xxxxxxxxx>
---
mm/mempolicy.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 81a1276..ceaf0d8 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1307,15 +1307,18 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
goto out;
/* Find the mm_struct */
+ rcu_read_lock();
read_lock(&tasklist_lock);
task = pid ? find_task_by_vpid(pid) : current;
if (!task) {
read_unlock(&tasklist_lock);
+ rcu_read_unlock();
err = -ESRCH;
goto out;
}
mm = get_task_mm(task);
read_unlock(&tasklist_lock);
+ rcu_read_unlock();
err = -EINVAL;
if (!mm)
--
1.7.0.4
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