linux-kernel - Re: [PATCH] soc: samsung: exynos-pmu: fix device leak on regmap lookup

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Message-ID: <fb573584-4027-4988-a703-7f619fa830fc@kernel.org>
Date: Fri, 21 Nov 2025 13:59:59 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Johan Hovold <johan@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>
Cc: Peter Griffin <peter.griffin@...aro.org>,
 linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
 stable@...r.kernel.org
Subject: Re: [PATCH] soc: samsung: exynos-pmu: fix device leak on regmap
 lookup

On 21/11/2025 13:18, Johan Hovold wrote:
> Make sure to drop the reference taken when looking up the PMU device and
> its regmap.
> 
> Note that holding a reference to a device does not prevent its regmap
> from going away so there is no point in keeping the reference.

Thanks for the patch, it's 3rd or fourth try from LKML on that, but you
were the only one actually really reading the code instead of sprinking
puts all around.

> 
> Fixes: 0b7c6075022c ("soc: samsung: exynos-pmu: Add regmap support for SoCs that protect PMU regs")
> Cc: stable@...r.kernel.org	# 6.9

Fix is fine, but unfortunately the code in v6.9 was different and I
believe keeping dev reference made sense there - driver was relying on
drvdata. While the leak was there as well, it was intentional. I think
the leak can be fixed only since commit
35d6b98c625867209bc47df99cf03edf4280799f .

Best regards,
Krzysztof