Commit-ID: 01b41159066531cc8d664362ff0cd89dd137bbfa Gitweb: http://git.kernel.org/tip/01b41159066531cc8d664362ff0cd89dd137bbfa Author: Lianwei Wang <[email protected]> AuthorDate: Thu, 9 Jun 2016 23:43:28 -0700 Committer: Thomas Gleixner <[email protected]> CommitDate: Fri, 2 Sep 2016 20:37:17 +0200
cpu/hotplug: Handle unbalanced hotplug enable/disable When cpu_hotplug_enable() is called unbalanced w/o a preceeding cpu_hotplug_disable() the code emits a warning, but happily decrements the disabled counter. This causes the next operations to malfunction. Prevent the decrement and just emit a warning. Signed-off-by: Lianwei Wang <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> --- kernel/cpu.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index c506485..c90f839 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -331,10 +331,17 @@ void cpu_hotplug_disable(void) } EXPORT_SYMBOL_GPL(cpu_hotplug_disable); +static void __cpu_hotplug_enable(void) +{ + if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) + return; + cpu_hotplug_disabled--; +} + 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); @@ -1160,7 +1167,7 @@ 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;
