Received-SPF: pass (google.com: domain of linux-kernel+bounces-169293-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: Levi Yun <ppbuk5246@gmail.com>
To: anna-maria@linutronix.de,
	frederic@kernel.org,
	tglx@linutronix.de,
	Markus.Elfring@web.de
Cc: linux-kernel@vger.kernel.org,
	Levi Yun <ppbuk5246@gmail.com>
Subject: [PATCH v3] time/timgr: Fix wrong reference when level 0 group allocation failed
Date: Mon,  6 May 2024 05:10:59 +0100
Message-ID: <20240506041059.86877-1-ppbuk5246@gmail.com>
In-Reply-To: <20240505085709.82688-1-ppbuk5246@gmail.com>
References: <20240505085709.82688-1-ppbuk5246@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

When tmigr_setup_groups() failed level 0 group allocation,
wrong reference happens on local stack array while intializing timer hierarchy.

To prevent this, Check loop condition first before initializing timer hierarchy.

Fixes: 7ee988770326 ("timers: Implement the hierarchical pull model")
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
---
v3:
    - Fix typo.

v2:
	- Modify commit message.

 kernel/time/timer_migration.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c
index ccba875d2234..84413114db5c 100644
--- a/kernel/time/timer_migration.c
+++ b/kernel/time/timer_migration.c
@@ -1596,7 +1596,7 @@ static int tmigr_setup_groups(unsigned int cpu, unsigned int node)

 	} while (i < tmigr_hierarchy_levels);

-	do {
+	while (i > 0) {
 		group = stack[--i];

 		if (err < 0) {
@@ -1645,7 +1645,7 @@ static int tmigr_setup_groups(unsigned int cpu, unsigned int node)
 				tmigr_connect_child_parent(child, group);
 			}
 		}
-	} while (i > 0);
+	}

 	kfree(stack);

--
2.41.0