On Wed, Jun 01, 2016 at 11:15:09AM -0700, Guenter Roeck wrote:
> It would be great if you can add at least part of the BUG message as well
> as a Fixes: tag into the patch description.
How's that:
---
From: Borislav Petkov <bp@xxxxxxx>
Date: Wed, 1 Jun 2016 11:36:13 +0200
Subject: [PATCH] hwmon: (fam15h_power) Disable preemption when reading registers
We need to read a bunch of registers on each compute unit and possibly
on the current CPU too. Disable preemption around it. Otherwise, you
get:
BUG: using smp_processor_id() in preemptible [00000000] code: systemd-udevd/327
caller is read_registers+0x6a/0x110 [fam15h_power]
CPU: 3 PID: 327 Comm: systemd-udevd Not tainted 4.7.0-rc1+ #4
Hardware name: HP HP EliteBook 745 G3/807E, BIOS N73 Ver. 01.08 01/28/2016
...
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Rui Huang <ray.huang@xxxxxxx>
Cc: Sherry Hurwitz <sherry.hurwitz@xxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Fixes: fa7943449943 ("hwmon: (fam15h_power) Add compute unit accumulated power")
---
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
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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