linux-kernel - Re: [PATCH v2] soc: samsung: exynos-pmu: fix reference leak in exynos_get_pmu_regmap_by

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Message-ID: <CAJKOXPcFzHYV0YWmWqA_ZoMBFyNSOjizBJi1-qLR73dPO0-qtg@mail.gmail.com>
Date: Sun, 28 Sep 2025 16:49:00 +0900
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Ma Ke <make24@...as.ac.cn>
Cc: alim.akhtar@...sung.com, semen.protsenko@...aro.org, 
	peter.griffin@...aro.org, linux-arm-kernel@...ts.infradead.org, 
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org, 
	akpm@...ux-foundation.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] soc: samsung: exynos-pmu: fix reference leak in exynos_get_pmu_regmap_by_phandle()

On Sun, 28 Sept 2025 at 16:04, Ma Ke <make24@...as.ac.cn> wrote:
>
> In exynos_get_pmu_regmap_by_phandle(), driver_find_device_by_of_node()
> utilizes driver_find_device_by_fwnode() which internally calls
> driver_find_device() to locate the matching device.
> driver_find_device() increments the reference count of the found
> device by calling get_device(), but exynos_get_pmu_regmap_by_phandle()
> fails to call put_device() to decrement the reference count before
> returning. This results in a reference count leak of the device each
> time exynos_get_pmu_regmap_by_phandle() is executed, which may prevent
> the device from being properly released and cause a memory leak.
>
> Since Exynos-PMU is a core system device that is not unloaded at
> runtime, and regmap is created during device probing, releasing the
> temporary device reference does not affect the validity of regmap.
> From the perspective of code standards and maintainability, reference
> count leakage is a genuine code defect that should be fixed. Even if
> the leakage does not immediately cause issues in certain scenarios,
> known leakage points should not be left unaddressed.
>
> Found by code review.
>
> Cc: stable@...r.kernel.org
> Fixes: 0b7c6075022c ("soc: samsung: exynos-pmu: Add regmap support for SoCs that protect PMU regs")
> Signed-off-by: Ma Ke <make24@...as.ac.cn>
> ---
> Changes in v2:
> - modified the typo of the variable in the patch. Sorry for the typo;


So it wasn't ever built. It's not a typo, it's lack of compiling, I do
not take such patches.

You didn't respond to my review, so same comments as before.