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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Lin Ma <linma@zju.edu.cn>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 030/218] ASoC: rt5645: Fix errorenous cleanup order
Date:   Mon, 13 Jun 2022 12:08:08 +0200
Message-Id: <20220613094915.390697663@linuxfoundation.org>
In-Reply-To: <20220613094908.257446132@linuxfoundation.org>
References: <20220613094908.257446132@linuxfoundation.org>
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From: Lin Ma <linma@zju.edu.cn>

[ Upstream commit 2def44d3aec59e38d2701c568d65540783f90f2f ]

There is a logic error when removing rt5645 device as the function
rt5645_i2c_remove() first cancel the &rt5645->jack_detect_work and
delete the &rt5645->btn_check_timer latter. However, since the timer
handler rt5645_btn_check_callback() will re-queue the jack_detect_work,
this cleanup order is buggy.

That is, once the del_timer_sync in rt5645_i2c_remove is concurrently
run with the rt5645_btn_check_callback, the canceled jack_detect_work
will be rescheduled again, leading to possible use-after-free.

This patch fix the issue by placing the del_timer_sync function before
the cancel_delayed_work_sync.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
Link: https://lore.kernel.org/r/20220516092035.28283-1-linma@zju.edu.cn
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/soc/codecs/rt5645.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/rt5645.c b/sound/soc/codecs/rt5645.c
index a98647ac497c..01de25813c72 100644
--- a/sound/soc/codecs/rt5645.c
+++ b/sound/soc/codecs/rt5645.c
@@ -3972,9 +3972,14 @@ static int rt5645_i2c_remove(struct i2c_client *i2c)
 	if (i2c->irq)
 		free_irq(i2c->irq, rt5645);
 
+	/*
+	 * Since the rt5645_btn_check_callback() can queue jack_detect_work,
+	 * the timer need to be delted first
+	 */
+	del_timer_sync(&rt5645->btn_check_timer);
+
 	cancel_delayed_work_sync(&rt5645->jack_detect_work);
 	cancel_delayed_work_sync(&rt5645->rcclock_work);
-	del_timer_sync(&rt5645->btn_check_timer);
 
 	snd_soc_unregister_codec(&i2c->dev);
 	regulator_bulk_disable(ARRAY_SIZE(rt5645->supplies), rt5645->supplies);
-- 
2.35.1