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Groups > linux.kernel > #1415892 > unrolled thread
| Started by | Keerthy <a0393675@ti.com> |
|---|---|
| First post | 2016-06-07 11:10 +0200 |
| Last post | 2016-06-07 11:30 +0200 |
| Articles | 2 — 1 participant |
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Re: [PATCH 02/15] thermal: sysfs: lock tz while on access to mode properties Keerthy <a0393675@ti.com> - 2016-06-07 11:10 +0200
Re: [PATCH 02/15] thermal: sysfs: lock tz while on access to mode properties Keerthy <a0393675@ti.com> - 2016-06-07 11:30 +0200
| From | Keerthy <a0393675@ti.com> |
|---|---|
| Date | 2016-06-07 11:10 +0200 |
| Subject | Re: [PATCH 02/15] thermal: sysfs: lock tz while on access to mode properties |
| Message-ID | <rHlbk-Mt-15@gated-at.bofh.it> |
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.
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;
>
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| From | Keerthy <a0393675@ti.com> |
|---|---|
| Date | 2016-06-07 11:30 +0200 |
| Message-ID | <rHluG-Te-29@gated-at.bofh.it> |
| In reply to | #1415892 |
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.
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;
>>
> --
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