From: Robert Foss <robert.foss@linaro.org> To: Johan Hovold <johan@kernel.org> Cc: Yu Kuai <yukuai3@huawei.com>, Andrzej Hajda <a.hajda@samsung.com>, Neil Armstrong <narmstrong@baylibre.com>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, dri-devel <dri-devel@lists.freedesktop.org>, linux-kernel <linux-kernel@vger.kernel.org>, yi.zhang@huawei.com Subject: Re: [PATCH] drm: bridge: cdns-mhdp8546: Fix PM reference leak in cdns_mhdp_probe() Date: Tue, 18 May 2021 14:58:32 +0200 [thread overview] Message-ID: <CAG3jFyu9x0NERFQ78GAX_6TUimB_PmBXkcVJZ9i+HXbK=N0dmQ@mail.gmail.com> (raw) In-Reply-To: <YKNv5fsVaTrslJZw@hovoldconsulting.com> On Tue, 18 May 2021 at 09:42, Johan Hovold <johan@kernel.org> wrote: > > On Mon, May 17, 2021 at 11:27:38AM +0200, Robert Foss wrote: > > Hey Yu, > > > > On Mon, 17 May 2021 at 10:08, Yu Kuai <yukuai3@huawei.com> 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 <hulkci@huawei.com> > > > Signed-off-by: Yu Kuai <yukuai3@huawei.com> > > > --- > > > drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > > > index 0cd8f40fb690..305489d48c16 100644 > > > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > > > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > > > @@ -2478,7 +2478,7 @@ static int cdns_mhdp_probe(struct platform_device *pdev) > > > clk_prepare_enable(clk); > > > > > > pm_runtime_enable(dev); > > > - ret = pm_runtime_get_sync(dev); > > > + ret = pm_runtime_resume_and_get(dev); > > > if (ret < 0) { > > > dev_err(dev, "pm_runtime_get_sync failed\n"); This error message is a bit confusing now, could you update it. > > > pm_runtime_disable(dev); > > > > The code is correct as it is. If pm_runtime_get_sync() fails and > > increments[1] the pm.usage_count variable, that isn't a problem since > > pm_runtime_disable() disables pm, and resets pm.usage_count variable > > to zero[2]. > > No it doesn't; pm_runtime_disable() does not reset the counter and you > still need to decrement the usage count when pm_runtime_get_sync() > fails. Thanks for chiming in Johan, you're absolutely right and I must have misread something. With the above fix, feel free to add my r-b. Reviewed-by: Robert Foss <robert.foss@linaro.org>
WARNING: multiple messages have this Message-ID (diff)
From: Robert Foss <robert.foss@linaro.org> To: Johan Hovold <johan@kernel.org> Cc: Neil Armstrong <narmstrong@baylibre.com>, David Airlie <airlied@linux.ie>, yi.zhang@huawei.com, linux-kernel <linux-kernel@vger.kernel.org>, dri-devel <dri-devel@lists.freedesktop.org>, Andrzej Hajda <a.hajda@samsung.com>, Yu Kuai <yukuai3@huawei.com> Subject: Re: [PATCH] drm: bridge: cdns-mhdp8546: Fix PM reference leak in cdns_mhdp_probe() Date: Tue, 18 May 2021 14:58:32 +0200 [thread overview] Message-ID: <CAG3jFyu9x0NERFQ78GAX_6TUimB_PmBXkcVJZ9i+HXbK=N0dmQ@mail.gmail.com> (raw) In-Reply-To: <YKNv5fsVaTrslJZw@hovoldconsulting.com> On Tue, 18 May 2021 at 09:42, Johan Hovold <johan@kernel.org> wrote: > > On Mon, May 17, 2021 at 11:27:38AM +0200, Robert Foss wrote: > > Hey Yu, > > > > On Mon, 17 May 2021 at 10:08, Yu Kuai <yukuai3@huawei.com> 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 <hulkci@huawei.com> > > > Signed-off-by: Yu Kuai <yukuai3@huawei.com> > > > --- > > > drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > > > index 0cd8f40fb690..305489d48c16 100644 > > > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > > > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > > > @@ -2478,7 +2478,7 @@ static int cdns_mhdp_probe(struct platform_device *pdev) > > > clk_prepare_enable(clk); > > > > > > pm_runtime_enable(dev); > > > - ret = pm_runtime_get_sync(dev); > > > + ret = pm_runtime_resume_and_get(dev); > > > if (ret < 0) { > > > dev_err(dev, "pm_runtime_get_sync failed\n"); This error message is a bit confusing now, could you update it. > > > pm_runtime_disable(dev); > > > > The code is correct as it is. If pm_runtime_get_sync() fails and > > increments[1] the pm.usage_count variable, that isn't a problem since > > pm_runtime_disable() disables pm, and resets pm.usage_count variable > > to zero[2]. > > No it doesn't; pm_runtime_disable() does not reset the counter and you > still need to decrement the usage count when pm_runtime_get_sync() > fails. Thanks for chiming in Johan, you're absolutely right and I must have misread something. With the above fix, feel free to add my r-b. Reviewed-by: Robert Foss <robert.foss@linaro.org>
next prev parent reply other threads:[~2021-05-18 12:58 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-17 8:16 [PATCH] drm: bridge: cdns-mhdp8546: Fix PM reference leak in cdns_mhdp_probe() Yu Kuai 2021-05-17 8:16 ` Yu Kuai 2021-05-17 9:27 ` Robert Foss 2021-05-17 9:27 ` Robert Foss 2021-05-17 12:34 ` yukuai (C) 2021-05-17 12:34 ` yukuai (C) 2021-05-18 7:42 ` Johan Hovold 2021-05-18 7:42 ` Johan Hovold 2021-05-18 12:58 ` Robert Foss [this message] 2021-05-18 12:58 ` Robert Foss 2021-05-29 9:15 ` yukuai (C) 2021-05-29 9:15 ` yukuai (C) 2021-05-29 9:55 ` [PATCH V2] " Yu Kuai 2021-05-29 9:55 ` Yu Kuai 2021-05-31 10:54 ` Robert Foss 2021-05-31 10:54 ` Robert Foss 2021-05-31 13:48 ` yukuai (C) 2021-05-31 13:48 ` yukuai (C)
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