From: Lianwei Wang Date: Fri, 10 Jun 2016 06:43:28 +0000 (-0700) Subject: UPSTREAM: cpu/hotplug: Handle unbalanced hotplug enable/disable X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=a3c8dc25c446485dcbf8a978f755eead9eac3671;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git UPSTREAM: cpu/hotplug: Handle unbalanced hotplug enable/disable (cherry picked from 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 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 --- diff --git a/kernel/cpu.c b/kernel/cpu.c index 9ced7c751648..c8a1751be224 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -185,10 +185,17 @@ 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); @@ -631,7 +638,7 @@ 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;