From 74559c69e8cdc3ad60bdb0fa88d77acc22342568 Mon Sep 17 00:00:00 2001 From: Lianwei Wang Date: Tue, 19 Apr 2016 23:36:20 -0700 Subject: [PATCH] cpu/hotplug: handle unbalanced hotplug enable/disable Currently it just print a warning message but did not reset cpu_hotplug_disabled when the enable/disable is unbalanced. The unbalanced enable/disable will lead the cpu hotplug work abnormally. Do nothing if an unablanced hotplug enable detected. Signed-off-by: Lianwei Wang --- kernel/cpu.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index d948e44c471ea8..cc0a6fc779f4d8 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -245,6 +245,19 @@ void cpu_hotplug_done(void) cpuhp_lock_release(); } +static void _cpu_hotplug_disable(void) +{ + cpu_hotplug_disabled++; +} + +static void _cpu_hotplug_enable(void) +{ + if (WARN(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) + return; + + cpu_hotplug_disabled--; +} + /* * Wait for currently running CPU hotplug operations to complete (if any) and * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects @@ -255,7 +268,7 @@ void cpu_hotplug_done(void) void cpu_hotplug_disable(void) { cpu_maps_update_begin(); - cpu_hotplug_disabled++; + _cpu_hotplug_disable(); cpu_maps_update_done(); } EXPORT_SYMBOL_GPL(cpu_hotplug_disable); @@ -263,7 +276,7 @@ EXPORT_SYMBOL_GPL(cpu_hotplug_disable); void cpu_hotplug_enable(void) { cpu_maps_update_begin(); - WARN_ON(--cpu_hotplug_disabled < 0); + _cpu_hotplug_enable(); cpu_maps_update_done(); } EXPORT_SYMBOL_GPL(cpu_hotplug_enable); @@ -1054,7 +1067,7 @@ int disable_nonboot_cpus(void) * this even in case of failure as all disable_nonboot_cpus() users are * supposed to do enable_nonboot_cpus() on the failure path. */ - cpu_hotplug_disabled++; + _cpu_hotplug_disable(); cpu_maps_update_done(); return error; @@ -1074,7 +1087,7 @@ void enable_nonboot_cpus(void) /* Allow everyone to use the CPU hotplug again */ cpu_maps_update_begin(); - WARN_ON(--cpu_hotplug_disabled < 0); + _cpu_hotplug_enable(); if (cpumask_empty(frozen_cpus)) goto out;