From ee92f8084e6a103f5ab1deddfa19c1165041d75f Mon Sep 17 00:00:00 2001
From: Phapoom Saksri <mind@blueskychan.dev>
Date: Fri, 28 Feb 2025 02:41:43 +0700
Subject: [PATCH] forgor

---
 include/linux/cred.h | 11 +++++++++++
 kernel/cred.c        |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/linux/cred.h b/include/linux/cred.h
index a99c2d35b7be..316f4074d223 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -286,6 +286,17 @@ static inline const struct cred *get_cred(const struct cred *cred)
 	return get_new_cred(nonconst_cred);
 }
 
+static inline const struct cred *get_cred_rcu(const struct cred *cred)
+{
+	struct cred *nonconst_cred = (struct cred *) cred;
+	if (!cred)
+		return NULL;
+	if (!atomic_long_inc_not_zero(&nonconst_cred->usage))
+		return NULL;
+	validate_creds(cred);
+	return cred;
+}
+
 /**
  * put_cred - Release a reference to a set of credentials
  * @cred: The credentials to release
diff --git a/kernel/cred.c b/kernel/cred.c
index bd8813455823..95d14cdae814 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -303,7 +303,7 @@ const struct cred *get_task_cred(struct task_struct *task)
 	do {
 		cred = __task_cred((task));
 		BUG_ON(!cred);
-	} while (!atomic_inc_not_zero(&((struct cred *)cred)->usage));
+	} while (!get_cred_rcu(cred));
 #endif /*CONFIG_RKP_KDP*/
 	rcu_read_unlock();
 	return cred;