rcu_report_dead() has to be called locally by the CPU that is going to
exit the RCU state machine. Passing a cpu argument here is error-prone
and leaves the possibility for a racy remote call.
Use local access instead.
Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
---
arch/arm64/kernel/smp.c | 2 +-
include/linux/rcupdate.h | 2 +-
kernel/cpu.c | 2 +-
kernel/rcu/tree.c | 4 ++--
4 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 960b98b43506..8fa646c90c67 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -401,7 +401,7 @@ void __noreturn cpu_die_early(void)
/* Mark this CPU absent */
set_cpu_present(cpu, 0);
- rcu_report_dead(cpu);
+ rcu_report_dead();
if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
update_cpu_boot_status(CPU_KILL_ME);
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 5e5f920ade90..aa351ddcbe8d 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -122,7 +122,7 @@ static inline void call_rcu_hurry(struct rcu_head *head, rcu_callback_t func)
void rcu_init(void);
extern int rcu_scheduler_active;
void rcu_sched_clock_irq(int user);
-void rcu_report_dead(unsigned int cpu);
+void rcu_report_dead(void);
void rcutree_migrate_callbacks(int cpu);
#ifdef CONFIG_TASKS_RCU_GENERIC
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6de7c6bb74ee..076e75fed8bb 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1388,7 +1388,7 @@ void cpuhp_report_idle_dead(void)
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
BUG_ON(st->state != CPUHP_AP_OFFLINE);
- rcu_report_dead(smp_processor_id());
+ rcu_report_dead();
st->state = CPUHP_AP_IDLE_DEAD;
/*
* We cannot call complete after rcu_report_dead() so we delegate it
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8c2954502e55..2e1e7eadf2cc 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4560,11 +4560,11 @@ void rcu_cpu_starting(unsigned int cpu)
* from the outgoing CPU rather than from the cpuhp_step mechanism.
* This is because this function must be invoked at a precise location.
*/
-void rcu_report_dead(unsigned int cpu)
+void rcu_report_dead(void)
{
unsigned long flags;
unsigned long mask;
- struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+ struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */
/*
--
2.34.1
