linux-kernel - [PATCH] input: synaptics_i2c - cancel delayed work before freeing device

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Message-Id: <20251210032027.11700-1-ii4gsp@gmail.com>
Date: Wed, 10 Dec 2025 12:20:27 +0900
From: Minseong Kim <ii4gsp@...il.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org,
	Minseong Kim <ii4gsp@...il.com>
Subject: [PATCH] input: synaptics_i2c - cancel delayed work before freeing device

synaptics_i2c_irq() schedules touch->dwork via mod_delayed_work().
The delayed work performs I2C transactions and may still be running
(or get queued) when the device is removed.

synaptics_i2c_remove() currently frees 'touch' without canceling
touch->dwork. If removal happens while the work is pending/running,
the work handler may dereference freed memory, leading to a potential
use-after-free.

Cancel the delayed work synchronously before unregistering/freeing
the device.

Fixes: eef3e4cab72e Input: add driver for Synaptics I2C touchpad
Reported-by: Minseong Kim <ii4gsp@...il.com>
Cc: stable@...r.kernel.org
Signed-off-by: Minseong Kim <ii4gsp@...il.com>
---
 drivers/input/mouse/synaptics_i2c.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/input/mouse/synaptics_i2c.c b/drivers/input/mouse/synaptics_i2c.c
index a0d707e47d93..fe30bf9aea3a 100644
--- a/drivers/input/mouse/synaptics_i2c.c
+++ b/drivers/input/mouse/synaptics_i2c.c
@@ -593,6 +593,8 @@ static void synaptics_i2c_remove(struct i2c_client *client)
 	if (!polling_req)
 		free_irq(client->irq, touch);
 
+	cancel_delayed_work_sync(&touch->dwork);
+
 	input_unregister_device(touch->input);
 	kfree(touch);
 }
-- 
2.39.5