On Wednesday, July 30, 2014 02:10:35 PM Gu Zheng wrote:
> Hi Rafael,
Hi,
> A lockdep warning occurs when hot removing a cpu via sysfs:
> echo 1 > /sys/bus/acpi/devices/LNXCPU\:02/eject
> The kernel is latest upstream, and the test box is a kvm vm,
> detail info as following.
Well, I have a theory.
Is the splat still reproducible with the patch below applied?
Rafael
---
kernel/smp.c | 2 ++
1 file changed, 2 insertions(+)
Index: linux-pm/kernel/smp.c
===================================================================
--- linux-pm.orig/kernel/smp.c
+++ linux-pm/kernel/smp.c
@@ -542,6 +542,7 @@ void __init smp_init(void)
idle_threads_init();
+ lock_device_hotplug();
/* FIXME: This should be done in userspace --RR */
for_each_present_cpu(cpu) {
if (num_online_cpus() >= setup_max_cpus)
@@ -549,6 +550,7 @@ void __init smp_init(void)
if (!cpu_online(cpu))
cpu_up(cpu);
}
+ unlock_device_hotplug();
/* Any cleanup work */
smp_announce();
--
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