perf/x86/amd: Fix AMD NB and L2I "uncore" support

Borislav Petkov reported a lockdep splat warning about kzalloc()
done in an IPI (hardirq) handler.

This is a real bug, do not call kzalloc() in a smp_call_function_single()
handler because it can schedule and crash.

Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: <eranian@google.com>
Cc: <a.p.zijlstra@chello.nl>
Cc: <acme@ghostprotocols.net>
Cc: <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20130421180627.GA21049@jshin-Toonie
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/perf_event_amd_uncore.c b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
index 6dc62273639cf5813098a780b18af83d958f1828..c0c661adf03e2efd9f0735719864913ca886a1f7 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_amd_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
@@ -498,7 +498,6 @@ static void __init init_cpu_already_online(void *dummy)
 {
        unsigned int cpu = smp_processor_id();
 
-       amd_uncore_cpu_up_prepare(cpu);
        amd_uncore_cpu_starting(cpu);
        amd_uncore_cpu_online(cpu);
 }
@@ -535,8 +534,10 @@ static int __init amd_uncore_init(void)
 
        get_online_cpus();
        /* init cpus already online before registering for hotplug notifier */
-       for_each_online_cpu(cpu)
+       for_each_online_cpu(cpu) {
+               amd_uncore_cpu_up_prepare(cpu);
                smp_call_function_single(cpu, init_cpu_already_online, NULL, 1);
+       }
 
        register_cpu_notifier(&amd_uncore_cpu_notifier_block);
        put_online_cpus();