From: Borislav Petkov <b...@suse.de>

We need to read a bunch of registers on each compute unit and possibly
on the current CPU too. Disable preemption around it.

Signed-off-by: Borislav Petkov <b...@suse.de>
Cc: Rui Huang <ray.hu...@amd.com>
Cc: Sherry Hurwitz <sherry.hurw...@amd.com>
Cc: Guenter Roeck <li...@roeck-us.net>
---
 drivers/hwmon/fam15h_power.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
index eb97a9241d17..69bb810f528b 100644
--- a/drivers/hwmon/fam15h_power.c
+++ b/drivers/hwmon/fam15h_power.c
@@ -172,9 +172,9 @@ static void do_read_registers_on_cu(void *_data)
  */
 static int read_registers(struct fam15h_power_data *data)
 {
-       int this_cpu, ret, cpu;
        int core, this_core;
        cpumask_var_t mask;
+       int ret, cpu;
 
        ret = zalloc_cpumask_var(&mask, GFP_KERNEL);
        if (!ret)
@@ -183,7 +183,6 @@ static int read_registers(struct fam15h_power_data *data)
        memset(data->cu_on, 0, sizeof(int) * MAX_CUS);
 
        get_online_cpus();
-       this_cpu = smp_processor_id();
 
        /*
         * Choose the first online core of each compute unit, and then
@@ -205,10 +204,13 @@ static int read_registers(struct fam15h_power_data *data)
                cpumask_set_cpu(cpumask_any(topology_sibling_cpumask(cpu)), 
mask);
        }
 
-       if (cpumask_test_cpu(this_cpu, mask))
+       preempt_disable();
+       smp_call_function_many(mask, do_read_registers_on_cu, data, true);
+
+       if (cpumask_test_cpu(smp_processor_id(), mask))
                do_read_registers_on_cu(data);
 
-       smp_call_function_many(mask, do_read_registers_on_cu, data, true);
+       preempt_enable();
        put_online_cpus();
 
        free_cpumask_var(mask);
-- 
2.7.3

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