Messages in this thread | | | From | Ulf Hansson <> | Date | Mon, 12 Jun 2017 14:57:21 +0200 | Subject | Re: [PATCH 2/8] PM / domains: Protect reading loop over list of domains |
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On 9 June 2017 at 18:16, Krzysztof Kozlowski <krzk@kernel.org> wrote: > On Fri, Jun 09, 2017 at 06:08:47PM +0200, Krzysztof Kozlowski wrote: >> The pm_genpd_present() iterates over list of domains so grabbing a >> gpd_list_lock mutex is necessary before calling it. Otherwise we could >> end up in iterating over and modifying the list at the same time. >> >> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> >> --- >> drivers/base/power/domain.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >> index 2e8d0f423507..2a6935dc0164 100644 >> --- a/drivers/base/power/domain.c >> +++ b/drivers/base/power/domain.c >> @@ -1099,8 +1099,13 @@ static void genpd_syscore_switch(struct device *dev, bool suspend) >> struct generic_pm_domain *genpd; >> >> genpd = dev_to_genpd(dev);
Actually there may be potential problem here as we may end up trying to use the container_of() call for a PM domain, not being a genpd but something else.
>> - if (!pm_genpd_present(genpd)) >> + >> + mutex_lock(&gpd_list_lock); >> + if (!pm_genpd_present(genpd)) { >> + mutex_unlock(&gpd_list_lock); >> return; >> + } >> + mutex_unlock(&gpd_list_lock);
Perhaps convert the hole thing above to call genpd_lookup_dev() instead?
> > Eh, I might be too fast as this is not executed on my platform. The > genpd_syscore_switch() seems to be called by clocksource_suspend() which > is called by syscore ops. Should be safe but actually not tested. > > Someone with SH hardware is needed... > > Best regards, > Krzysztof >
Kind regards Uffe
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