| From bbe2c87d36fb253b9d025ffe8452afde01284514 Mon Sep 17 00:00:00 2001 |
| From: Lianwei Wang <lianwei.wang@gmail.com> |
| Date: Thu, 9 Jun 2016 23:43:28 -0700 |
| Subject: cpu/hotplug: Handle unbalanced hotplug enable/disable |
| |
| [ Upstream commit 01b41159066531cc8d664362ff0cd89dd137bbfa ] |
| |
| 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 <lianwei.wang@gmail.com> |
| Cc: peterz@infradead.org |
| Cc: linux-pm@vger.kernel.org |
| Cc: oleg@redhat.com |
| Link: http://lkml.kernel.org/r/1465541008-12476-1-git-send-email-lianwei.wang@gmail.com |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| kernel/cpu.c | 11 +++++++++-- |
| 1 file changed, 9 insertions(+), 2 deletions(-) |
| |
| diff --git a/kernel/cpu.c b/kernel/cpu.c |
| index 40d20bf5de28..42ce0b0ae5c5 100644 |
| --- a/kernel/cpu.c |
| +++ b/kernel/cpu.c |
| @@ -183,10 +183,17 @@ 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); |
| @@ -626,7 +633,7 @@ 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; |
| |
| -- |
| 2.19.1 |
| |
