2019-03-21 00:35:50

by Joel Fernandes

[permalink] [raw]
Subject: [PATCH v2 0/4] RCU fixes for rcu_assign_pointer() usage

This is just a resend with scheduler patches split from the driver fixes and
Paul's Reviewed-by(s) added.

These patches fix various sparse errors ccaused as a result of the recent check
to add rcu_check_sparse() to rcu_assign_pointer(). The errors are due to
missing annotations. The annotations added in the series can also help avoid
future incorrect usages and bugs so it is a good idea to do in any case.

RFC v1 -> Patch v2:
Made changes based on Peter Zijlstra review.

Joel Fernandes (Google) (4):
sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu
sched_domain: Annotate RCU pointers properly
rcuwait: Annotate task_struct with __rcu
sched: Annotate perf_domain pointer with __rcu

include/linux/rcuwait.h | 2 +-
include/linux/sched/topology.h | 4 ++--
kernel/sched/cpufreq.c | 2 +-
kernel/sched/sched.h | 18 +++++++++---------
kernel/sched/topology.c | 10 +++++-----
5 files changed, 18 insertions(+), 18 deletions(-)

--
2.21.0.225.g810b269d1ac-goog



2019-03-21 00:35:53

by Joel Fernandes

[permalink] [raw]
Subject: [PATCH v2 1/4] sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu

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.

[From an RCU perspective]
Reviewed-by: Paul E. McKenney <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
---
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 835671f0f917..b5dcd1d83c7f 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 efa686eeff26..713715dd00cf 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2185,7 +2185,7 @@ 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.
--
2.21.0.225.g810b269d1ac-goog


2019-03-21 00:35:57

by Joel Fernandes

[permalink] [raw]
Subject: [PATCH v2 3/4] rcuwait: Annotate task_struct with __rcu

This suppresses sparse error generated due to the recently added
rcu_assign_pointer sparse check.

percpu-rwsem.c:162:9: sparse: error: incompatible types in comparison expression
exit.c:316:16: sparse: error: incompatible types in comparison expression

[From an RCU perspective]
Reviewed-by: Paul E. McKenney <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
---
include/linux/rcuwait.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
index 90bfa3279a01..563290fc194f 100644
--- a/include/linux/rcuwait.h
+++ b/include/linux/rcuwait.h
@@ -18,7 +18,7 @@
* awoken.
*/
struct rcuwait {
- struct task_struct *task;
+ struct task_struct __rcu *task;
};

#define __RCUWAIT_INITIALIZER(name) \
--
2.21.0.225.g810b269d1ac-goog


2019-03-21 00:36:07

by Joel Fernandes

[permalink] [raw]
Subject: [PATCH v2 4/4] sched: Annotate perf_domain pointer with __rcu

This fixes the following sparse errors in sched/fair.c:

fair.c:6506:14: error: incompatible types in comparison expression
fair.c:8642:21: error: incompatible types in comparison expression

Using __rcu will also help sparse catch any future bugs.

[From an RCU perspective]
Reviewed-by: Paul E. McKenney <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
---
kernel/sched/sched.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 2b452d68ab2e..b52ed1ada0be 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -780,7 +780,7 @@ struct root_domain {
* NULL-terminated list of performance domains intersecting with the
* CPUs of the rd. Protected by RCU.
*/
- struct perf_domain *pd;
+ struct perf_domain __rcu *pd;
};

extern struct root_domain def_root_domain;
--
2.21.0.225.g810b269d1ac-goog


2019-03-21 00:38:03

by Joel Fernandes

[permalink] [raw]
Subject: [PATCH v2 2/4] sched_domain: Annotate RCU pointers properly

The scheduler uses RCU API in various places to access sched_domain
pointers. These cause sparse errors as below.

Many new errors show up because of an annotation check I added to
rcu_assign_pointer(). Let us annotate the pointers correctly which also
will help sparse catch any potential future bugs.

This fixes the following sparse errors:

rt.c:1681:9: error: incompatible types in comparison expression
deadline.c:1904:9: error: incompatible types in comparison expression
core.c:519:9: error: incompatible types in comparison expression
core.c:1634:17: error: incompatible types in comparison expression
fair.c:6193:14: error: incompatible types in comparison expression
fair.c:9883:22: error: incompatible types in comparison expression
fair.c:9897:9: error: incompatible types in comparison expression
sched.h:1287:9: error: incompatible types in comparison expression
topology.c:612:9: error: incompatible types in comparison expression
topology.c:615:9: error: incompatible types in comparison expression
sched.h:1300:9: error: incompatible types in comparison expression
topology.c:618:9: error: incompatible types in comparison expression
sched.h:1287:9: error: incompatible types in comparison expression
topology.c:621:9: error: incompatible types in comparison expression
sched.h:1300:9: error: incompatible types in comparison expression
topology.c:624:9: error: incompatible types in comparison expression
topology.c:671:9: error: incompatible types in comparison expression
stats.c:45:17: error: incompatible types in comparison expression
fair.c:5998:15: error: incompatible types in comparison expression
fair.c:5989:15: error: incompatible types in comparison expression
fair.c:5998:15: error: incompatible types in comparison expression
fair.c:5989:15: error: incompatible types in comparison expression
fair.c:6120:19: error: incompatible types in comparison expression
fair.c:6506:14: error: incompatible types in comparison expression
fair.c:6515:14: error: incompatible types in comparison expression
fair.c:6623:9: error: incompatible types in comparison expression
fair.c:5970:17: error: incompatible types in comparison expression
fair.c:8642:21: error: incompatible types in comparison expression
fair.c:9253:9: error: incompatible types in comparison expression
fair.c:9331:9: error: incompatible types in comparison expression
fair.c:9519:15: error: incompatible types in comparison expression
fair.c:9533:14: error: incompatible types in comparison expression
fair.c:9542:14: error: incompatible types in comparison expression
fair.c:9567:14: error: incompatible types in comparison expression
fair.c:9597:14: error: incompatible types in comparison expression
fair.c:9421:16: error: incompatible types in comparison expression
fair.c:9421:16: error: incompatible types in comparison expression

[From an RCU perspective]
Reviewed-by: Paul E. McKenney <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
---
include/linux/sched/topology.h | 4 ++--
kernel/sched/sched.h | 14 +++++++-------
kernel/sched/topology.c | 10 +++++-----
3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 57c7ed3fe465..cfc0a89a7159 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -76,8 +76,8 @@ struct sched_domain_shared {

struct sched_domain {
/* These fields must be setup */
- struct sched_domain *parent; /* top domain must be null terminated */
- struct sched_domain *child; /* bottom domain must be null terminated */
+ struct sched_domain __rcu *parent; /* top domain must be null terminated */
+ struct sched_domain __rcu *child; /* bottom domain must be null terminated */
struct sched_group *groups; /* the balancing groups of the domain */
unsigned long min_interval; /* Minimum balance interval ms */
unsigned long max_interval; /* Maximum balance interval ms */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 713715dd00cf..2b452d68ab2e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -869,8 +869,8 @@ struct rq {
atomic_t nr_iowait;

#ifdef CONFIG_SMP
- struct root_domain *rd;
- struct sched_domain *sd;
+ struct root_domain *rd;
+ struct sched_domain __rcu *sd;

unsigned long cpu_capacity;
unsigned long cpu_capacity_orig;
@@ -1324,13 +1324,13 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
return sd;
}

-DECLARE_PER_CPU(struct sched_domain *, sd_llc);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
-DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DECLARE_PER_CPU(struct sched_domain *, sd_numa);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
extern struct static_key_false sched_asym_cpucapacity;

struct sched_group_capacity {
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index ab7f371a3a17..64bec54ded3e 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -615,13 +615,13 @@ static void destroy_sched_domains(struct sched_domain *sd)
* the cpumask of the domain), this allows us to quickly tell if
* two CPUs are in the same cache domain, see cpus_share_cache().
*/
-DEFINE_PER_CPU(struct sched_domain *, sd_llc);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DEFINE_PER_CPU(int, sd_llc_size);
DEFINE_PER_CPU(int, sd_llc_id);
-DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DEFINE_PER_CPU(struct sched_domain *, sd_numa);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);

static void update_top_cache_domain(int cpu)
--
2.21.0.225.g810b269d1ac-goog


2019-03-21 18:02:25

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH v2 0/4] RCU fixes for rcu_assign_pointer() usage

On Wed, Mar 20, 2019 at 08:34:22PM -0400, Joel Fernandes (Google) wrote:
> This is just a resend with scheduler patches split from the driver fixes and
> Paul's Reviewed-by(s) added.
>
> These patches fix various sparse errors ccaused as a result of the recent check
> to add rcu_check_sparse() to rcu_assign_pointer(). The errors are due to
> missing annotations. The annotations added in the series can also help avoid
> future incorrect usages and bugs so it is a good idea to do in any case.
>
> RFC v1 -> Patch v2:
> Made changes based on Peter Zijlstra review.
>
> Joel Fernandes (Google) (4):
> sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu
> sched_domain: Annotate RCU pointers properly
> rcuwait: Annotate task_struct with __rcu
> sched: Annotate perf_domain pointer with __rcu
>
> include/linux/rcuwait.h | 2 +-
> include/linux/sched/topology.h | 4 ++--
> kernel/sched/cpufreq.c | 2 +-
> kernel/sched/sched.h | 18 +++++++++---------
> kernel/sched/topology.c | 10 +++++-----
> 5 files changed, 18 insertions(+), 18 deletions(-)

Thanks Joel

2019-03-21 20:13:43

by Luc Van Oostenryck

[permalink] [raw]
Subject: Re: [PATCH v2 0/4] RCU fixes for rcu_assign_pointer() usage

On Wed, Mar 20, 2019 at 08:34:22PM -0400, Joel Fernandes (Google) wrote:
> This is just a resend with scheduler patches split from the driver fixes and
> Paul's Reviewed-by(s) added.
>
> These patches fix various sparse errors ccaused as a result of the recent check
> to add rcu_check_sparse() to rcu_assign_pointer(). The errors are due to
> missing annotations. The annotations added in the series can also help avoid
> future incorrect usages and bugs so it is a good idea to do in any case.
>
> RFC v1 -> Patch v2:
> Made changes based on Peter Zijlstra review.
>
> Joel Fernandes (Google) (4):
> sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu
> sched_domain: Annotate RCU pointers properly
> rcuwait: Annotate task_struct with __rcu
> sched: Annotate perf_domain pointer with __rcu
>
> include/linux/rcuwait.h | 2 +-
> include/linux/sched/topology.h | 4 ++--
> kernel/sched/cpufreq.c | 2 +-
> kernel/sched/sched.h | 18 +++++++++---------
> kernel/sched/topology.c | 10 +++++-----
> 5 files changed, 18 insertions(+), 18 deletions(-)

Looks good to me.

-- Luc

Subject: [tip:sched/core] sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu

Commit-ID: 8f9affdf4094bde418a0dbd8b52bb503ee486469
Gitweb: https://git.kernel.org/tip/8f9affdf4094bde418a0dbd8b52bb503ee486469
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:23 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 09:51:01 +0200

sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu

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) <[email protected]>
[ From an RCU perspective. ]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
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 835671f0f917..b5dcd1d83c7f 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 efa686eeff26..713715dd00cf 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2185,7 +2185,7 @@ 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.

Subject: [tip:sched/core] sched_domain: Annotate RCU pointers properly

Commit-ID: 8e000ec0716d953f905e8f8ca2a6c71bb31bbf5d
Gitweb: https://git.kernel.org/tip/8e000ec0716d953f905e8f8ca2a6c71bb31bbf5d
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:24 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 09:51:03 +0200

sched_domain: Annotate RCU pointers properly

The scheduler uses RCU API in various places to access sched_domain
pointers. These cause sparse errors as below.

Many new errors show up because of an annotation check I added to
rcu_assign_pointer(). Let us annotate the pointers correctly which also
will help sparse catch any potential future bugs.

This fixes the following sparse errors:

rt.c:1681:9: error: incompatible types in comparison expression
deadline.c:1904:9: error: incompatible types in comparison expression
core.c:519:9: error: incompatible types in comparison expression
core.c:1634:17: error: incompatible types in comparison expression
fair.c:6193:14: error: incompatible types in comparison expression
fair.c:9883:22: error: incompatible types in comparison expression
fair.c:9897:9: error: incompatible types in comparison expression
sched.h:1287:9: error: incompatible types in comparison expression
topology.c:612:9: error: incompatible types in comparison expression
topology.c:615:9: error: incompatible types in comparison expression
sched.h:1300:9: error: incompatible types in comparison expression
topology.c:618:9: error: incompatible types in comparison expression
sched.h:1287:9: error: incompatible types in comparison expression
topology.c:621:9: error: incompatible types in comparison expression
sched.h:1300:9: error: incompatible types in comparison expression
topology.c:624:9: error: incompatible types in comparison expression
topology.c:671:9: error: incompatible types in comparison expression
stats.c:45:17: error: incompatible types in comparison expression
fair.c:5998:15: error: incompatible types in comparison expression
fair.c:5989:15: error: incompatible types in comparison expression
fair.c:5998:15: error: incompatible types in comparison expression
fair.c:5989:15: error: incompatible types in comparison expression
fair.c:6120:19: error: incompatible types in comparison expression
fair.c:6506:14: error: incompatible types in comparison expression
fair.c:6515:14: error: incompatible types in comparison expression
fair.c:6623:9: error: incompatible types in comparison expression
fair.c:5970:17: error: incompatible types in comparison expression
fair.c:8642:21: error: incompatible types in comparison expression
fair.c:9253:9: error: incompatible types in comparison expression
fair.c:9331:9: error: incompatible types in comparison expression
fair.c:9519:15: error: incompatible types in comparison expression
fair.c:9533:14: error: incompatible types in comparison expression
fair.c:9542:14: error: incompatible types in comparison expression
fair.c:9567:14: error: incompatible types in comparison expression
fair.c:9597:14: error: incompatible types in comparison expression
fair.c:9421:16: error: incompatible types in comparison expression
fair.c:9421:16: error: incompatible types in comparison expression

Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
[ From an RCU perspective. ]
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
include/linux/sched/topology.h | 4 ++--
kernel/sched/sched.h | 14 +++++++-------
kernel/sched/topology.c | 10 +++++-----
3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 57c7ed3fe465..cfc0a89a7159 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -76,8 +76,8 @@ struct sched_domain_shared {

struct sched_domain {
/* These fields must be setup */
- struct sched_domain *parent; /* top domain must be null terminated */
- struct sched_domain *child; /* bottom domain must be null terminated */
+ struct sched_domain __rcu *parent; /* top domain must be null terminated */
+ struct sched_domain __rcu *child; /* bottom domain must be null terminated */
struct sched_group *groups; /* the balancing groups of the domain */
unsigned long min_interval; /* Minimum balance interval ms */
unsigned long max_interval; /* Maximum balance interval ms */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 713715dd00cf..2b452d68ab2e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -869,8 +869,8 @@ struct rq {
atomic_t nr_iowait;

#ifdef CONFIG_SMP
- struct root_domain *rd;
- struct sched_domain *sd;
+ struct root_domain *rd;
+ struct sched_domain __rcu *sd;

unsigned long cpu_capacity;
unsigned long cpu_capacity_orig;
@@ -1324,13 +1324,13 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
return sd;
}

-DECLARE_PER_CPU(struct sched_domain *, sd_llc);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
-DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DECLARE_PER_CPU(struct sched_domain *, sd_numa);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
extern struct static_key_false sched_asym_cpucapacity;

struct sched_group_capacity {
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index ab7f371a3a17..64bec54ded3e 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -615,13 +615,13 @@ static void destroy_sched_domains(struct sched_domain *sd)
* the cpumask of the domain), this allows us to quickly tell if
* two CPUs are in the same cache domain, see cpus_share_cache().
*/
-DEFINE_PER_CPU(struct sched_domain *, sd_llc);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DEFINE_PER_CPU(int, sd_llc_size);
DEFINE_PER_CPU(int, sd_llc_id);
-DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DEFINE_PER_CPU(struct sched_domain *, sd_numa);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);

static void update_top_cache_domain(int cpu)

Subject: [tip:sched/core] sched/core: Annotate perf_domain pointer with __rcu

Commit-ID: 2e7d58babd2a6073d1afb38519e246dd4a423da5
Gitweb: https://git.kernel.org/tip/2e7d58babd2a6073d1afb38519e246dd4a423da5
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:26 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 09:51:04 +0200

sched/core: Annotate perf_domain pointer with __rcu

This fixes the following sparse errors in sched/fair.c:

fair.c:6506:14: error: incompatible types in comparison expression
fair.c:8642:21: error: incompatible types in comparison expression

Using __rcu will also help sparse catch any future bugs.

Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
[ From an RCU perspective. ]
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched/sched.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 2b452d68ab2e..b52ed1ada0be 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -780,7 +780,7 @@ struct root_domain {
* NULL-terminated list of performance domains intersecting with the
* CPUs of the rd. Protected by RCU.
*/
- struct perf_domain *pd;
+ struct perf_domain __rcu *pd;
};

extern struct root_domain def_root_domain;

Subject: [tip:sched/core] rcuwait: Annotate task_struct with __rcu

Commit-ID: ea3ce866b568e087737df666c2c035496f54fdcb
Gitweb: https://git.kernel.org/tip/ea3ce866b568e087737df666c2c035496f54fdcb
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:25 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 09:51:04 +0200

rcuwait: Annotate task_struct with __rcu

This suppresses sparse error generated due to the recently added
rcu_assign_pointer sparse check.

percpu-rwsem.c:162:9: sparse: error: incompatible types in comparison expression
exit.c:316:16: sparse: error: incompatible types in comparison expression

Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
[ From an RCU perspective. ]
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
include/linux/rcuwait.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
index 90bfa3279a01..563290fc194f 100644
--- a/include/linux/rcuwait.h
+++ b/include/linux/rcuwait.h
@@ -18,7 +18,7 @@
* awoken.
*/
struct rcuwait {
- struct task_struct *task;
+ struct task_struct __rcu *task;
};

#define __RCUWAIT_INITIALIZER(name) \

Subject: [tip:sched/core] rcuwait: Annotate task_struct with __rcu

Commit-ID: 03f4b48edae7d936c5bf23488c1ce3fbe7fc2733
Gitweb: https://git.kernel.org/tip/03f4b48edae7d936c5bf23488c1ce3fbe7fc2733
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:25 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 12:34:31 +0200

rcuwait: Annotate task_struct with __rcu

This suppresses sparse error generated due to the recently added
rcu_assign_pointer sparse check.

percpu-rwsem.c:162:9: sparse: error: incompatible types in comparison expression
exit.c:316:16: sparse: error: incompatible types in comparison expression

Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
[ From an RCU perspective. ]
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
include/linux/rcuwait.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
index 90bfa3279a01..563290fc194f 100644
--- a/include/linux/rcuwait.h
+++ b/include/linux/rcuwait.h
@@ -18,7 +18,7 @@
* awoken.
*/
struct rcuwait {
- struct task_struct *task;
+ struct task_struct __rcu *task;
};

#define __RCUWAIT_INITIALIZER(name) \

Subject: [tip:sched/core] sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu

Commit-ID: b10abd0a8859493a93c6b8020f2be2587557749d
Gitweb: https://git.kernel.org/tip/b10abd0a8859493a93c6b8020f2be2587557749d
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:23 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 12:34:31 +0200

sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu

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) <[email protected]>
[ From an RCU perspective. ]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
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 835671f0f917..b5dcd1d83c7f 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 efa686eeff26..713715dd00cf 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2185,7 +2185,7 @@ 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.

Subject: [tip:sched/core] sched_domain: Annotate RCU pointers properly

Commit-ID: 994aeb7a93e43d28f6074195ccb03a384342e1bf
Gitweb: https://git.kernel.org/tip/994aeb7a93e43d28f6074195ccb03a384342e1bf
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:24 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 12:34:31 +0200

sched_domain: Annotate RCU pointers properly

The scheduler uses RCU API in various places to access sched_domain
pointers. These cause sparse errors as below.

Many new errors show up because of an annotation check I added to
rcu_assign_pointer(). Let us annotate the pointers correctly which also
will help sparse catch any potential future bugs.

This fixes the following sparse errors:

rt.c:1681:9: error: incompatible types in comparison expression
deadline.c:1904:9: error: incompatible types in comparison expression
core.c:519:9: error: incompatible types in comparison expression
core.c:1634:17: error: incompatible types in comparison expression
fair.c:6193:14: error: incompatible types in comparison expression
fair.c:9883:22: error: incompatible types in comparison expression
fair.c:9897:9: error: incompatible types in comparison expression
sched.h:1287:9: error: incompatible types in comparison expression
topology.c:612:9: error: incompatible types in comparison expression
topology.c:615:9: error: incompatible types in comparison expression
sched.h:1300:9: error: incompatible types in comparison expression
topology.c:618:9: error: incompatible types in comparison expression
sched.h:1287:9: error: incompatible types in comparison expression
topology.c:621:9: error: incompatible types in comparison expression
sched.h:1300:9: error: incompatible types in comparison expression
topology.c:624:9: error: incompatible types in comparison expression
topology.c:671:9: error: incompatible types in comparison expression
stats.c:45:17: error: incompatible types in comparison expression
fair.c:5998:15: error: incompatible types in comparison expression
fair.c:5989:15: error: incompatible types in comparison expression
fair.c:5998:15: error: incompatible types in comparison expression
fair.c:5989:15: error: incompatible types in comparison expression
fair.c:6120:19: error: incompatible types in comparison expression
fair.c:6506:14: error: incompatible types in comparison expression
fair.c:6515:14: error: incompatible types in comparison expression
fair.c:6623:9: error: incompatible types in comparison expression
fair.c:5970:17: error: incompatible types in comparison expression
fair.c:8642:21: error: incompatible types in comparison expression
fair.c:9253:9: error: incompatible types in comparison expression
fair.c:9331:9: error: incompatible types in comparison expression
fair.c:9519:15: error: incompatible types in comparison expression
fair.c:9533:14: error: incompatible types in comparison expression
fair.c:9542:14: error: incompatible types in comparison expression
fair.c:9567:14: error: incompatible types in comparison expression
fair.c:9597:14: error: incompatible types in comparison expression
fair.c:9421:16: error: incompatible types in comparison expression
fair.c:9421:16: error: incompatible types in comparison expression

Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
[ From an RCU perspective. ]
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
include/linux/sched/topology.h | 4 ++--
kernel/sched/sched.h | 14 +++++++-------
kernel/sched/topology.c | 10 +++++-----
3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 57c7ed3fe465..cfc0a89a7159 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -76,8 +76,8 @@ struct sched_domain_shared {

struct sched_domain {
/* These fields must be setup */
- struct sched_domain *parent; /* top domain must be null terminated */
- struct sched_domain *child; /* bottom domain must be null terminated */
+ struct sched_domain __rcu *parent; /* top domain must be null terminated */
+ struct sched_domain __rcu *child; /* bottom domain must be null terminated */
struct sched_group *groups; /* the balancing groups of the domain */
unsigned long min_interval; /* Minimum balance interval ms */
unsigned long max_interval; /* Maximum balance interval ms */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 713715dd00cf..2b452d68ab2e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -869,8 +869,8 @@ struct rq {
atomic_t nr_iowait;

#ifdef CONFIG_SMP
- struct root_domain *rd;
- struct sched_domain *sd;
+ struct root_domain *rd;
+ struct sched_domain __rcu *sd;

unsigned long cpu_capacity;
unsigned long cpu_capacity_orig;
@@ -1324,13 +1324,13 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
return sd;
}

-DECLARE_PER_CPU(struct sched_domain *, sd_llc);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
-DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DECLARE_PER_CPU(struct sched_domain *, sd_numa);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
extern struct static_key_false sched_asym_cpucapacity;

struct sched_group_capacity {
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index ab7f371a3a17..64bec54ded3e 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -615,13 +615,13 @@ static void destroy_sched_domains(struct sched_domain *sd)
* the cpumask of the domain), this allows us to quickly tell if
* two CPUs are in the same cache domain, see cpus_share_cache().
*/
-DEFINE_PER_CPU(struct sched_domain *, sd_llc);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DEFINE_PER_CPU(int, sd_llc_size);
DEFINE_PER_CPU(int, sd_llc_id);
-DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DEFINE_PER_CPU(struct sched_domain *, sd_numa);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);

static void update_top_cache_domain(int cpu)

Subject: [tip:sched/core] sched/core: Annotate perf_domain pointer with __rcu

Commit-ID: 7ba7319f9e3898101bff5d63cbae5a6cc174c8c9
Gitweb: https://git.kernel.org/tip/7ba7319f9e3898101bff5d63cbae5a6cc174c8c9
Author: Joel Fernandes (Google) <[email protected]>
AuthorDate: Wed, 20 Mar 2019 20:34:26 -0400
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 3 Apr 2019 12:34:31 +0200

sched/core: Annotate perf_domain pointer with __rcu

This fixes the following sparse errors in sched/fair.c:

fair.c:6506:14: error: incompatible types in comparison expression
fair.c:8642:21: error: incompatible types in comparison expression

Using __rcu will also help sparse catch any future bugs.

Signed-off-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
[ From an RCU perspective. ]
Reviewed-by: Paul E. McKenney <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched/sched.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 2b452d68ab2e..b52ed1ada0be 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -780,7 +780,7 @@ struct root_domain {
* NULL-terminated list of performance domains intersecting with the
* CPUs of the rd. Protected by RCU.
*/
- struct perf_domain *pd;
+ struct perf_domain __rcu *pd;
};

extern struct root_domain def_root_domain;