Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | Re: ACPI/cpu hotplug: possible lockdep | Date | Wed, 30 Jul 2014 15:12:49 +0200 |
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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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