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From: Phil Chang <phil.chang@mediatek.com>
To: <anna-maria@linutronix.de>
CC: <alix.wu@mediatek.com>, <angelogioacchino.delregno@collabora.com>,
	<frederic@kernel.org>, <jy.ho@mediatek.com>,
	<linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
	<matthias.bgg@gmail.com>, <phil.chang@mediatek.com>, <tglx@linutronix.de>
Subject: [PATCH v2] hrtimer: check hrtimer with a NULL function
Date: Fri, 7 Jun 2024 10:26:14 +0800
Message-ID: <20240607022614.22902-1-phil.chang@mediatek.com>
In-Reply-To: <877cf2i56q.fsf@somnus>
References: <877cf2i56q.fsf@somnus>
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MIME-Version: 1.0
Content-Type: text/plain

Since hrtimers do not allow a NULL function to be passed,
to prevent a kernel crash, return before adding the timer to a queue.

Signed-off-by: Phil Chang <phil.chang@mediatek.com>
---
 kernel/time/hrtimer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 492c14aac642..d32c1afe59b3 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1285,6 +1285,9 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
 	struct hrtimer_clock_base *base;
 	unsigned long flags;
 
+	if (WARN_ON(!timer->function))
+		return;
+
 	/*
 	 * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
 	 * match on CONFIG_PREEMPT_RT = n. With PREEMPT_RT check the hard
-- 
2.18.0