linux-kernel - [PATCH] Input: Fix a ref counting issue

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Date:   Sun, 29 Nov 2020 09:45:16 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     dmitry.torokhov@...il.com, rydberg@...omail.se, tj@...nel.org
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH] Input: Fix a ref counting issue

In case of a managed resource, 'devm_input_device_release()' already has a
'input_put_device(dev)' call.

Avoid a double reference decrement by explicitly calling
'input_put_device()' only on non-managed input device.

Fixes: 2be975c6d920 ("Input: introduce managed input devices (add devres support)")
Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
This patch is completely speculative and compile tested only.
---
 drivers/input/input.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/input/input.c b/drivers/input/input.c
index 3cfd2c18eebd..c09c9f020667 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -1920,7 +1920,8 @@ void input_free_device(struct input_dev *dev)
 						devm_input_device_release,
 						devm_input_device_match,
 						dev));
-		input_put_device(dev);
+		else
+			input_put_device(dev);
 	}
 }
 EXPORT_SYMBOL(input_free_device);
-- 
2.27.0