lkml.org 
[lkml]   [2015]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 1/2] PM / OPP: Assert RCU lock in exported functions
Date
On Friday, January 09, 2015 09:27:57 AM Krzysztof Kozlowski wrote:
> Add lockdep asserts for holding the RCU lock when calling
> dev_pm_opp_get_freq() and dev_pm_opp_get_voltage() to aid in detecting
> RCU misuses.
>
> These are called often after dev_pm_opp_find_freq_ceil/exact() which
> already asserts for RCU lock. However one could make an error by
> releasing lock too early - just after dev_pm_opp_find_freq_ceil().
>
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Queued up for 3.20, thanks!

> ---
> drivers/base/power/opp.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index 106c69359306..842d31e24eee 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -169,6 +169,8 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
> struct dev_pm_opp *tmp_opp;
> unsigned long v = 0;
>
> + opp_rcu_lockdep_assert();
> +
> tmp_opp = rcu_dereference(opp);
> if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
> pr_err("%s: Invalid parameters\n", __func__);
> @@ -199,6 +201,8 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
> struct dev_pm_opp *tmp_opp;
> unsigned long f = 0;
>
> + opp_rcu_lockdep_assert();
> +
> tmp_opp = rcu_dereference(opp);
> if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
> pr_err("%s: Invalid parameters\n", __func__);
>

--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.


\
 
 \ /
  Last update: 2015-01-30 01:01    [W:0.054 / U:0.276 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site