From: Zhang Rui <rui.zhang@intel.com>
To: Keerthy <a0393675@ti.com>, Eduardo Valentin <edubezval@gmail.com>
Cc: Linux PM <linux-pm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"R, Vignesh" <vigneshr@ti.com>
Subject: Re: [PATCH 02/15] thermal: sysfs: lock tz while on access to mode properties
Date: Wed, 22 Jun 2016 10:45:38 +0800 [thread overview]
Message-ID: <1466563538.2471.10.camel@intel.com> (raw)
In-Reply-To: <5756923F.6010007@ti.com>
On 二, 2016-06-07 at 14:52 +0530, Keerthy wrote:
>
> On Tuesday 07 June 2016 02:38 PM, Keerthy wrote:
> >
> > Hi Eduardo,
> >
> > On Tuesday 31 May 2016 12:01 PM, Eduardo Valentin wrote:
> > >
> > > Serialized calls to tz.ops in user facing
> > > sysfs handler mode_show() and mode_store().
> > This seems to be causing a deadlock at boot time during the ending
> > stages of boot:
> >
> > http://pastebin.ubuntu.com/17085291/
> >
> > It took a while to git bisect on linux-next.
> >
> > Seems like you introduced new locking at the sysfs layer which
> > causes
> > this deadlock as the underlying code again tries to acquire the
> > same
> > tz->lock.
> I confirm reverting this patch helps me boot on linux-next. This
> patch
> can be dropped as the lower layer functions are already acquiring tz-
> >lock.
>
> Thanks Vignesh for reporting the deadlock.
>
the root cause of the deadlock is that some platform driver invokes
thermal_zone_device_update() in .set_mode(), after mode changed.
If we wants to lock tz->ops->set_mode(), we should cleanup all the
platform thermal drivers, and deliver a thermal_zone_device_update()
in mode_store(), at the same time.
thanks,
rui
> Regards,
> Keerthy
>
> >
> >
> > Regards,
> > Keerthy
> >
> > >
> > >
> > > Cc: Zhang Rui <rui.zhang@intel.com>
> > > Cc: linux-pm@vger.kernel.org
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
> > > ---
> > > drivers/thermal/thermal_sysfs.c | 13 ++++++++++---
> > > 1 file changed, 10 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/thermal/thermal_sysfs.c
> > > b/drivers/thermal/thermal_sysfs.c
> > > index ee983ca..1db2406 100644
> > > --- a/drivers/thermal/thermal_sysfs.c
> > > +++ b/drivers/thermal/thermal_sysfs.c
> > > @@ -62,7 +62,9 @@ mode_show(struct device *dev, struct
> > > device_attribute *attr, char *buf)
> > > if (!tz->ops->get_mode)
> > > return -EPERM;
> > >
> > > + mutex_lock(&tz->lock);
> > > result = tz->ops->get_mode(tz, &mode);
> > > + mutex_unlock(&tz->lock);
> > > if (result)
> > > return result;
> > >
> > > @@ -75,17 +77,22 @@ mode_store(struct device *dev, struct
> > > device_attribute *attr,
> > > const char *buf, size_t count)
> > > {
> > > struct thermal_zone_device *tz = to_thermal_zone(dev);
> > > + enum thermal_device_mode mode = THERMAL_DEVICE_DISABLED;
> > > int result;
> > >
> > > if (!tz->ops->set_mode)
> > > return -EPERM;
> > >
> > > if (!strncmp(buf, "enabled", sizeof("enabled") - 1))
> > > - result = tz->ops->set_mode(tz, THERMAL_DEVICE_ENABLED);
> > > + mode = THERMAL_DEVICE_ENABLED;
> > > else if (!strncmp(buf, "disabled", sizeof("disabled") - 1))
> > > - result = tz->ops->set_mode(tz, THERMAL_DEVICE_DISABLED);
> > > + mode = THERMAL_DEVICE_DISABLED;
> > > else
> > > - result = -EINVAL;
> > > + return -EINVAL;
> > > +
> > > + mutex_lock(&tz->lock);
> > > + result = tz->ops->set_mode(tz, mode);
> > > + mutex_unlock(&tz->lock);
> > >
> > > if (result)
> > > return result;
> > >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pm"
> > in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2016-06-22 2:47 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 6:31 [PATCH 00/15] thermal: sysfs: add locking Eduardo Valentin
2016-05-31 6:31 ` [PATCH 01/15] thermal: sysfs: lock tz in type_show Eduardo Valentin
2016-05-31 6:31 ` [PATCH 02/15] thermal: sysfs: lock tz while on access to mode properties Eduardo Valentin
2016-06-07 9:08 ` Keerthy
2016-06-07 9:22 ` Keerthy
2016-06-22 2:45 ` Zhang Rui [this message]
2016-06-22 5:06 ` [PATCH 1/1] thermal: core: call thermal_zone_device_update() after mode update Eduardo Valentin
2016-06-23 12:27 ` Rafael J. Wysocki
2016-06-23 12:37 ` Keerthy
2016-07-01 20:53 ` Eduardo Valentin
2016-06-22 5:15 ` [PATCHv2 " Eduardo Valentin
2016-06-22 9:33 ` Keerthy
2016-06-22 14:36 ` Eduardo Valentin
2016-06-22 15:05 ` Eduardo Valentin
2016-06-22 14:34 ` [PATCHv3 " Eduardo Valentin
2016-06-22 15:03 ` [PATCHv4 " Eduardo Valentin
2016-06-23 4:38 ` Keerthy
2016-06-23 4:51 ` Darren Hart
2016-06-29 6:23 ` Zhang Rui
2016-07-01 20:57 ` Eduardo Valentin
2016-07-03 9:03 ` Peter Feuerer
2016-07-02 2:49 ` [PATCHv2 1/1] thermal: sysfs: lock tz while on access to mode properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 03/15] thermal: sysfs: lock tz while on trip_point_type properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 04/15] thermal: sysfs: lock tz while on trip_point_temp properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 05/15] thermal: sysfs: lock tz while on trip_point_hyst properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 06/15] thermal: sysfs: lock tz while on passive properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 07/15] thermal: sysfs: lock tz while on policy properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 08/15] thermal: sysfs: improve locking of emul_temp_store() Eduardo Valentin
2016-05-31 6:31 ` [PATCH 09/15] thermal: sysfs: lock tz when access sustainable power properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 10/15] thermal: sysfs: lock tz when access tzp properties Eduardo Valentin
2016-05-31 6:31 ` [PATCH 11/15] thermal: sysfs: lock cdev while accessing type Eduardo Valentin
2016-05-31 6:31 ` [PATCH 12/15] thermal: sysfs: lock cdev while accessing max_state Eduardo Valentin
2016-05-31 6:31 ` [PATCH 13/15] thermal: sysfs: lock cdev while accessing cur_state Eduardo Valentin
2016-05-31 6:31 ` [PATCH 14/15] thermal: sysfs: serialize access to instances Eduardo Valentin
2016-05-31 6:31 ` [PATCH 15/15] thermal: sysfs: add comments describing locking strategy Eduardo Valentin
2016-06-01 3:56 ` [PATCH 00/15] thermal: sysfs: add locking Keerthy
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