linux-kernel - [tip: smp/core] cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot

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Date:   Sat, 28 Mar 2020 10:48:13 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Boqun Feng <boqun.feng@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Pavankumar Kondeti <pkondeti@...eaurora.org>,
        stable@...r.kernel.org, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: smp/core] cpu/hotplug: Ignore pm_wakeup_pending() for
 disable_nonboot_cpus()

The following commit has been merged into the smp/core branch of tip:

Commit-ID:     e98eac6ff1b45e4e73f2e6031b37c256ccb5d36b
Gitweb:        https://git.kernel.org/tip/e98eac6ff1b45e4e73f2e6031b37c256ccb5d36b
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Fri, 27 Mar 2020 12:06:44 +01:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Sat, 28 Mar 2020 11:42:55 +01:00

cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus()

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@...il.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Pavankumar Kondeti <pkondeti@...eaurora.org>
Cc: stable@...r.kernel.org
Link: https://lkml.kernel.org/r/874kuaxdiz.fsf@nanos.tec.linutronix.de


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

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 9ead281..beaed2d 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -144,12 +144,18 @@ static inline void get_online_cpus(void) { cpus_read_lock(); }
 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)
 {
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 3084849..12ae636 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1327,7 +1327,7 @@ void bringup_nonboot_cpus(unsigned int setup_max_cpus)
 #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;
 
@@ -1352,7 +1352,7 @@ 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;