[PATCH 5.5 126/257] cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus()

[Greg Kroah-Hartman]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

commit e98eac6ff1b45e4e73f2e6031b37c256ccb5d36b upstream.

A recent change to freeze_secondary_cpus() which added an early abort if a
wakeup is pending missed the fact that the function is also invoked for
shutdown, reboot and kexec via disable_nonboot_cpus().

In case of disable_nonboot_cpus() the wakeup event needs to be ignored as
the purpose is to terminate the currently running kernel.

Add a 'suspend' argument which is only set when the freeze is in context of
a suspend operation. If not set then an eventually pending wakeup event is
ignored.

Fixes: a66d955e910a ("cpu/hotplug: Abort disabling secondary CPUs if wakeup is pending")
Reported-by: Boqun Feng <boqun.feng@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Pavankumar Kondeti <pkondeti@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/874kuaxdiz.fsf@xxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 include/linux/cpu.h |   12 +++++++++---
 kernel/cpu.c        |    4 ++--
 2 files changed, 11 insertions(+), 5 deletions(-)

--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -138,12 +138,18 @@ static inline void get_online_cpus(void)
 static inline void put_online_cpus(void) { cpus_read_unlock(); }
 
 #ifdef CONFIG_PM_SLEEP_SMP
-extern int freeze_secondary_cpus(int primary);
+int __freeze_secondary_cpus(int primary, bool suspend);
+static inline int freeze_secondary_cpus(int primary)
+{
+	return __freeze_secondary_cpus(primary, true);
+}
+
 static inline int disable_nonboot_cpus(void)
 {
-	return freeze_secondary_cpus(0);
+	return __freeze_secondary_cpus(0, false);
 }
-extern void enable_nonboot_cpus(void);
+
+void enable_nonboot_cpus(void);
 
 static inline int suspend_disable_secondary_cpus(void)
 {
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1212,7 +1212,7 @@ EXPORT_SYMBOL_GPL(cpu_up);
 #ifdef CONFIG_PM_SLEEP_SMP
 static cpumask_var_t frozen_cpus;
 
-int freeze_secondary_cpus(int primary)
+int __freeze_secondary_cpus(int primary, bool suspend)
 {
 	int cpu, error = 0;
 
@@ -1237,7 +1237,7 @@ int freeze_secondary_cpus(int primary)
 		if (cpu == primary)
 			continue;
 
-		if (pm_wakeup_pending()) {
+		if (suspend && pm_wakeup_pending()) {
 			pr_info("Wakeup pending. Abort CPU freeze\n");
 			error = -EBUSY;
 			break;