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Message-Id: <20190321003426.160260-3-joel@joelfernandes.org>
Date: Wed, 20 Mar 2019 20:34:24 -0400
From: "Joel Fernandes (Google)" <joel@...lfernandes.org>
To: linux-kernel@...r.kernel.org
Cc: "Joel Fernandes (Google)" <joel@...lfernandes.org>,
"Paul E . McKenney" <paulmck@...ux.ibm.com>,
Ingo Molnar <mingo@...hat.com>,
Josh Triplett <josh@...htriplett.org>,
keescook@...omium.org,
kernel-hardening@...ts.openwall.com,
kernel-team@...roid.com,
Lai Jiangshan <jiangshanlai@...il.com>,
Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Morten Rasmussen <morten.rasmussen@....com>,
Peter Zijlstra <peterz@...radead.org>,
rcu@...r.kernel.org,
Steven Rostedt <rostedt@...dmis.org>
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 <paulmck@...ux.ibm.com>
Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
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
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