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Mon, 31 May 2021 09:19:19 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lne4q-00BgyP-7D for linux-arm-kernel@lists.infradead.org; Mon, 31 May 2021 09:19:17 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id C689060FF1; Mon, 31 May 2021 09:19:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622452755; bh=nozaX3CwRzwSzPSuRttrxZ/WShcDLg1Y3tv/nTEUHVo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=El69CPY9uAwbdQlQZguYmB6351yG/qF7xl6IhDhY86PUY/q2NWIQZ9kH3x7ydsU1p 9PG24K3H+LkckdrJZUXa/2Cef0BKK86OgldwlrEadvoThxSUDP7XJEOqzRsK378Z0k YkIjgxqkMxx8sXwKeqcEuNLtG5iZdWz7y/RjkHvYh82pBKwIeqIaWDBpVeZz/m0d+M yd4AaXTRVC6M6kV3c6UpROceAilwCblLodK5gY+OyfUrEcBZnkkchqyouc5vFuao1J bXuem+oVRLDsH75T59zSCx4s1k4qP42XFdqkDWANS3IuH0djlN7EMRFosFRnKb1QF3 IQD0CvSLoHMzg== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1lne4l-00027o-0Y; Mon, 31 May 2021 11:19:11 +0200 Date: Mon, 31 May 2021 11:19:11 +0200 From: Johan Hovold To: Vinod Koul Cc: "yukuai (C)" , mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, michal.simek@xilinx.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, yi.zhang@huawei.com Subject: Re: [PATCH 2/3] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Message-ID: References: <20210517081826.1564698-1-yukuai3@huawei.com> <20210517081826.1564698-3-yukuai3@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210531_021916_308439_60CB15BB X-CRM114-Status: GOOD ( 26.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, May 31, 2021 at 02:27:34PM +0530, Vinod Koul wrote: > On 31-05-21, 14:11, yukuai (C) wrote: > > On 2021/05/31 12:00, Vinod Koul wrote: > > > On 17-05-21, 16:18, Yu Kuai wrote: > > > > pm_runtime_get_sync will increment pm usage counter even it failed. > > > > Forgetting to putting operation will result in reference leak here. > > > > Fix it by replacing it with pm_runtime_resume_and_get to keep usage > > > > counter balanced. > > > > > > > > Reported-by: Hulk Robot > > > > Signed-off-by: Yu Kuai > > > > --- > > > > drivers/dma/sh/usb-dmac.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/dma/sh/usb-dmac.c b/drivers/dma/sh/usb-dmac.c > > > > index 8f7ceb698226..2a6c8fd8854e 100644 > > > > --- a/drivers/dma/sh/usb-dmac.c > > > > +++ b/drivers/dma/sh/usb-dmac.c > > > > @@ -796,7 +796,7 @@ static int usb_dmac_probe(struct platform_device *pdev) > > > > /* Enable runtime PM and initialize the device. */ > > > > pm_runtime_enable(&pdev->dev); > > > > - ret = pm_runtime_get_sync(&pdev->dev); > > > > + ret = pm_runtime_resume_and_get(&pdev->dev); > > > > > > This does not seem to fix anything.. the below goto goes and disables > > > the runtime_pm for this device and thus there wont be any leak > > Hi, > > > > If pm_runtime_get_sync() fails and increments the pm.usage_count > > variable, pm_runtime_disable() does not reset the counter, and > > we still need to decrement the usage count when pm_runtime_get_sync() > > fails. Do I miss anthing? > > Yes the rumtime_pm is disabled on failure here and the count would have > no consequence... You should still balance the PM usage counter as it isn't reset for example when reloading the driver. Using pm_runtime_resume_and_get() is one way of handling this, but alternatively you could also move the error_pm label above the pm_runtime_put() in the error path. Johan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel