From: Daniel Thompson <danielt@kernel.org>
To: Guangshuo Li <lgs201920130244@gmail.com>
Cc: Olivia Mackall <olivia@selenic.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
Linus Walleij <linusw@kernel.org>,
linux-crypto@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] hwrng: stm32: fix usage_count leak when autosuspend_delay is negative
Date: Mon, 10 Aug 2026 11:24:41 +0100 [thread overview]
Message-ID: <anmm6X4MLpyIH8K1@aspen.lan> (raw)
In-Reply-To: <20260808074510.2655473-1-lgs201920130244@gmail.com>
On Sat, Aug 08, 2026 at 03:45:10PM +0800, Guangshuo Li wrote:
> stm32_rng_probe() calls pm_runtime_use_autosuspend(), but neither the
> probe failure path nor stm32_rng_remove() calls the matching
> pm_runtime_dont_use_autosuspend() before disabling runtime PM.
>
> If the autosuspend delay is set to a negative value while autosuspend
> is enabled, the runtime PM core increments usage_count to prevent
> runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
> during teardown, this reference is not dropped and usage_count remains
> unbalanced.
If calls to pm_runtime_use_autosuspend() must be paired with
pm_runtime_dont_use_autosuspend() then I wonder if having a
devm_pm_runtime_use_autosuspend() would be worthwhile?
That way stm32_rng_remove() could be entirely replaced with devres
cleanup.
Daniel.
prev parent reply other threads:[~2026-08-10 10:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-08 7:45 [PATCH] hwrng: stm32: fix usage_count leak when autosuspend_delay is negative Guangshuo Li
2026-08-10 10:24 ` Daniel Thompson [this message]
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