linux-kernel - [PATCH AUTOSEL 4.9 20/24] ASoC: rt5645: Fix errorenous cleanup order

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Message-Id: <20220530135211.1937674-20-sashal@kernel.org>
Date:   Mon, 30 May 2022 09:52:07 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Lin Ma <linma@....edu.cn>, Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>, oder_chiou@...ltek.com,
        lgirdwood@...il.com, perex@...ex.cz, tiwai@...e.com,
        alsa-devel@...a-project.org
Subject: [PATCH AUTOSEL 4.9 20/24] ASoC: rt5645: Fix errorenous cleanup order

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

diff --git a/sound/soc/codecs/rt5645.c b/sound/soc/codecs/rt5645.c
index 1ac96ef9ee20..703b26ec4e15 100644
--- a/sound/soc/codecs/rt5645.c
+++ b/sound/soc/codecs/rt5645.c
@@ -3878,6 +3878,12 @@ 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);
 
-- 
2.35.1