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([101.76.249.46]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-84f5a58dce5sm1891208b3a.58.2026.08.08.00.38.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 08 Aug 2026 00:38:04 -0700 (PDT) From: Guangshuo Li To: Andrew Jeffery , Avi Fishman , Tomer Maimon , Tali Perry , Patrick Venture , Nancy Yuen , Benjamin Fair , Olivia Mackall , Herbert Xu , Daniel Thompson , openbmc@lists.ozlabs.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Guangshuo Li , stable@vger.kernel.org Subject: [PATCH] hwrng: npcm: fix usage_count leak when autosuspend_delay is negative Date: Sat, 8 Aug 2026 15:37:48 +0800 Message-ID: <20260808073748.2649808-1-lgs201920130244@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" npcm_rng_probe() calls pm_runtime_use_autosuspend(), but neither the probe failure path nor npcm_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. Add the missing pm_runtime_dont_use_autosuspend() calls to both the probe failure and remove paths before disabling runtime PM. This issue was found by manual code inspection. Fixes: c98429297d8b ("hwrng: npcm - add NPCM RNG driver") Cc: stable@vger.kernel.org Signed-off-by: Guangshuo Li --- drivers/char/hw_random/npcm-rng.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/char/hw_random/npcm-rng.c b/drivers/char/hw_random/npc= m-rng.c index 40d6e29dea03..43f96abee753 100644 --- a/drivers/char/hw_random/npcm-rng.c +++ b/drivers/char/hw_random/npcm-rng.c @@ -118,6 +118,7 @@ static int npcm_rng_probe(struct platform_device *pdev) if (ret) { dev_err(&pdev->dev, "Failed to register rng device: %d\n", ret); + pm_runtime_dont_use_autosuspend(&pdev->dev); pm_runtime_disable(&pdev->dev); pm_runtime_set_suspended(&pdev->dev); return ret; @@ -131,6 +132,7 @@ static void npcm_rng_remove(struct platform_device *pde= v) struct npcm_rng *priv =3D platform_get_drvdata(pdev); =20 devm_hwrng_unregister(&pdev->dev, &priv->rng); + pm_runtime_dont_use_autosuspend(&pdev->dev); pm_runtime_disable(&pdev->dev); pm_runtime_set_suspended(&pdev->dev); } --=20 2.43.0