| Message ID | 20190223063434.6793-4-joel@joelfernandes.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | RCU fixes for rcu_assign_pointer() usage | expand |
On Sat, Feb 23, 2019 at 01:34:31AM -0500, Joel Fernandes (Google) wrote: > Recently I added an RCU annotation check to rcu_assign_pointer(). All > pointers assigned to RCU protected data are to be annotated with __rcu > inorder to be able to use rcu_assign_pointer() similar to checks in > other RCU APIs. > > This resulted in a sparse error: kernel//sched/cpufreq.c:41:9: sparse: > error: incompatible types in comparison expression (different address > spaces) > > Fix this by annotating cpufreq_update_util_data pointer with __rcu. This > will also help sparse catch any future RCU misuage bugs. > > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> From an RCU perspective: Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com> > --- > kernel/sched/cpufreq.c | 2 +- > kernel/sched/sched.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c > index 22bd8980f32f..e316ee7bb2e5 100644 > --- a/kernel/sched/cpufreq.c > +++ b/kernel/sched/cpufreq.c > @@ -7,7 +7,7 @@ > */ > #include "sched.h" > > -DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); > +DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); > > /** > * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index d04530bf251f..2ab545d40381 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -2166,7 +2166,7 @@ static inline u64 irq_time_read(int cpu) > #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ > > #ifdef CONFIG_CPU_FREQ > -DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); > +DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); > > /** > * cpufreq_update_util - Take a note about CPU utilization changes. > -- > 2.21.0.rc0.258.g878e2cd30e-goog >
On Mon, Feb 25, 2019 at 01:10:26PM -0800, Paul E. McKenney wrote: > On Sat, Feb 23, 2019 at 01:34:31AM -0500, Joel Fernandes (Google) wrote: > > Recently I added an RCU annotation check to rcu_assign_pointer(). All > > pointers assigned to RCU protected data are to be annotated with __rcu > > inorder to be able to use rcu_assign_pointer() similar to checks in > > other RCU APIs. > > > > This resulted in a sparse error: kernel//sched/cpufreq.c:41:9: sparse: > > error: incompatible types in comparison expression (different address > > spaces) > > > > Fix this by annotating cpufreq_update_util_data pointer with __rcu. This > > will also help sparse catch any future RCU misuage bugs. > > > > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> > > From an RCU perspective: > > Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com> Thanks a lot Paul. Peter, Rafael, Steve, Are you Ok with the patches 3-6? It will be nice to quiet down sparse. thanks, - Joel > > --- > > kernel/sched/cpufreq.c | 2 +- > > kernel/sched/sched.h | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c > > index 22bd8980f32f..e316ee7bb2e5 100644 > > --- a/kernel/sched/cpufreq.c > > +++ b/kernel/sched/cpufreq.c > > @@ -7,7 +7,7 @@ > > */ > > #include "sched.h" > > > > -DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); > > +DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); > > > > /** > > * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > > index d04530bf251f..2ab545d40381 100644 > > --- a/kernel/sched/sched.h > > +++ b/kernel/sched/sched.h > > @@ -2166,7 +2166,7 @@ static inline u64 irq_time_read(int cpu) > > #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ > > > > #ifdef CONFIG_CPU_FREQ > > -DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); > > +DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); > > > > /** > > * cpufreq_update_util - Take a note about CPU utilization changes. > > -- > > 2.21.0.rc0.258.g878e2cd30e-goog > > >
diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c index 22bd8980f32f..e316ee7bb2e5 100644 --- a/kernel/sched/cpufreq.c +++ b/kernel/sched/cpufreq.c @@ -7,7 +7,7 @@ */ #include "sched.h" -DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); +DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); /** * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d04530bf251f..2ab545d40381 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2166,7 +2166,7 @@ static inline u64 irq_time_read(int cpu) #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ #ifdef CONFIG_CPU_FREQ -DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); +DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); /** * cpufreq_update_util - Take a note about CPU utilization changes.
Recently I added an RCU annotation check to rcu_assign_pointer(). All pointers assigned to RCU protected data are to be annotated with __rcu inorder to be able to use rcu_assign_pointer() similar to checks in other RCU APIs. This resulted in a sparse error: kernel//sched/cpufreq.c:41:9: sparse: error: incompatible types in comparison expression (different address spaces) Fix this by annotating cpufreq_update_util_data pointer with __rcu. This will also help sparse catch any future RCU misuage bugs. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> --- kernel/sched/cpufreq.c | 2 +- kernel/sched/sched.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)