| Message ID | 20170609160853.31789-3-krzk@kernel.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
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); > - 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); 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
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
On Mon, Jun 12, 2017 at 02:57:21PM +0200, Ulf Hansson wrote: > 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? Indeed, that would solve both problems. Thanks, I'll fix this. Best regards, Krzysztof
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); - 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); if (suspend) { genpd->suspended_count++;
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(-)