2017-06-18 17:14:20 +00:00
|
|
|
From: Thomas Gleixner <tglx@linutronix.de>
|
|
|
|
Date: Wed, 12 Apr 2017 22:07:34 +0200
|
|
|
|
Subject: [PATCH 08/13] ACPI/processor: Replace racy task affinity logic
|
2017-07-16 20:28:09 +00:00
|
|
|
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.9-rt7.tar.xz
|
2017-06-18 17:14:20 +00:00
|
|
|
|
|
|
|
acpi_processor_get_throttling() requires to invoke the getter function on
|
|
|
|
the target CPU. This is achieved by temporarily setting the affinity of the
|
|
|
|
calling user space thread to the requested CPU and reset it to the original
|
|
|
|
affinity afterwards.
|
|
|
|
|
|
|
|
That's racy vs. CPU hotplug and concurrent affinity settings for that
|
|
|
|
thread resulting in code executing on the wrong CPU and overwriting the
|
|
|
|
new affinity setting.
|
|
|
|
|
|
|
|
acpi_processor_get_throttling() is invoked in two ways:
|
|
|
|
|
|
|
|
1) The CPU online callback, which is already running on the target CPU and
|
|
|
|
obviously protected against hotplug and not affected by affinity
|
|
|
|
settings.
|
|
|
|
|
|
|
|
2) The ACPI driver probe function, which is not protected against hotplug
|
|
|
|
during modprobe.
|
|
|
|
|
|
|
|
Switch it over to work_on_cpu() and protect the probe function against CPU
|
|
|
|
hotplug.
|
|
|
|
|
|
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
|
|
Cc: Fenghua Yu <fenghua.yu@intel.com>
|
|
|
|
Cc: Tony Luck <tony.luck@intel.com>
|
|
|
|
Cc: Herbert Xu <herbert@gondor.apana.org.au>
|
|
|
|
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
|
|
|
|
Cc: Peter Zijlstra <peterz@infradead.org>
|
|
|
|
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
|
|
|
|
Cc: Sebastian Siewior <bigeasy@linutronix.de>
|
|
|
|
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
|
|
|
|
Cc: linux-acpi@vger.kernel.org
|
|
|
|
Cc: Viresh Kumar <viresh.kumar@linaro.org>
|
|
|
|
Cc: Michael Ellerman <mpe@ellerman.id.au>
|
|
|
|
Cc: Tejun Heo <tj@kernel.org>
|
|
|
|
Cc: "David S. Miller" <davem@davemloft.net>
|
|
|
|
Cc: Len Brown <lenb@kernel.org>
|
|
|
|
Link: http://lkml.kernel.org/r/20170412201042.785920903@linutronix.de
|
|
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
|
|
---
|
|
|
|
drivers/acpi/processor_driver.c | 7 +++-
|
|
|
|
drivers/acpi/processor_throttling.c | 62 ++++++++++++++++++++----------------
|
|
|
|
2 files changed, 42 insertions(+), 27 deletions(-)
|
|
|
|
|
|
|
|
--- a/drivers/acpi/processor_driver.c
|
|
|
|
+++ b/drivers/acpi/processor_driver.c
|
|
|
|
@@ -262,11 +262,16 @@ static int __acpi_processor_start(struct
|
|
|
|
static int acpi_processor_start(struct device *dev)
|
|
|
|
{
|
|
|
|
struct acpi_device *device = ACPI_COMPANION(dev);
|
|
|
|
+ int ret;
|
|
|
|
|
|
|
|
if (!device)
|
|
|
|
return -ENODEV;
|
|
|
|
|
|
|
|
- return __acpi_processor_start(device);
|
|
|
|
+ /* Protect against concurrent CPU hotplug operations */
|
|
|
|
+ get_online_cpus();
|
|
|
|
+ ret = __acpi_processor_start(device);
|
|
|
|
+ put_online_cpus();
|
|
|
|
+ return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int acpi_processor_stop(struct device *dev)
|
|
|
|
--- a/drivers/acpi/processor_throttling.c
|
|
|
|
+++ b/drivers/acpi/processor_throttling.c
|
|
|
|
@@ -62,8 +62,8 @@ struct acpi_processor_throttling_arg {
|
|
|
|
#define THROTTLING_POSTCHANGE (2)
|
|
|
|
|
|
|
|
static int acpi_processor_get_throttling(struct acpi_processor *pr);
|
|
|
|
-int acpi_processor_set_throttling(struct acpi_processor *pr,
|
|
|
|
- int state, bool force);
|
|
|
|
+static int __acpi_processor_set_throttling(struct acpi_processor *pr,
|
|
|
|
+ int state, bool force, bool direct);
|
|
|
|
|
|
|
|
static int acpi_processor_update_tsd_coord(void)
|
|
|
|
{
|
|
|
|
@@ -891,7 +891,8 @@ static int acpi_processor_get_throttling
|
|
|
|
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
|
|
|
|
"Invalid throttling state, reset\n"));
|
|
|
|
state = 0;
|
|
|
|
- ret = acpi_processor_set_throttling(pr, state, true);
|
|
|
|
+ ret = __acpi_processor_set_throttling(pr, state, true,
|
|
|
|
+ true);
|
|
|
|
if (ret)
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
@@ -901,36 +902,31 @@ static int acpi_processor_get_throttling
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
-static int acpi_processor_get_throttling(struct acpi_processor *pr)
|
|
|
|
+static long __acpi_processor_get_throttling(void *data)
|
|
|
|
{
|
|
|
|
- cpumask_var_t saved_mask;
|
|
|
|
- int ret;
|
|
|
|
+ struct acpi_processor *pr = data;
|
|
|
|
+
|
|
|
|
+ return pr->throttling.acpi_processor_get_throttling(pr);
|
|
|
|
+}
|
|
|
|
|
|
|
|
+static int acpi_processor_get_throttling(struct acpi_processor *pr)
|
|
|
|
+{
|
|
|
|
if (!pr)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
if (!pr->flags.throttling)
|
|
|
|
return -ENODEV;
|
|
|
|
|
|
|
|
- if (!alloc_cpumask_var(&saved_mask, GFP_KERNEL))
|
|
|
|
- return -ENOMEM;
|
|
|
|
-
|
|
|
|
/*
|
|
|
|
- * Migrate task to the cpu pointed by pr.
|
|
|
|
+ * This is either called from the CPU hotplug callback of
|
|
|
|
+ * processor_driver or via the ACPI probe function. In the latter
|
|
|
|
+ * case the CPU is not guaranteed to be online. Both call sites are
|
|
|
|
+ * protected against CPU hotplug.
|
|
|
|
*/
|
|
|
|
- cpumask_copy(saved_mask, ¤t->cpus_allowed);
|
|
|
|
- /* FIXME: use work_on_cpu() */
|
|
|
|
- if (set_cpus_allowed_ptr(current, cpumask_of(pr->id))) {
|
|
|
|
- /* Can't migrate to the target pr->id CPU. Exit */
|
|
|
|
- free_cpumask_var(saved_mask);
|
|
|
|
+ if (!cpu_online(pr->id))
|
|
|
|
return -ENODEV;
|
|
|
|
- }
|
|
|
|
- ret = pr->throttling.acpi_processor_get_throttling(pr);
|
|
|
|
- /* restore the previous state */
|
|
|
|
- set_cpus_allowed_ptr(current, saved_mask);
|
|
|
|
- free_cpumask_var(saved_mask);
|
|
|
|
|
|
|
|
- return ret;
|
|
|
|
+ return work_on_cpu(pr->id, __acpi_processor_get_throttling, pr);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
|
|
|
|
@@ -1080,8 +1076,15 @@ static long acpi_processor_throttling_fn
|
|
|
|
arg->target_state, arg->force);
|
|
|
|
}
|
|
|
|
|
|
|
|
-int acpi_processor_set_throttling(struct acpi_processor *pr,
|
|
|
|
- int state, bool force)
|
|
|
|
+static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct)
|
|
|
|
+{
|
|
|
|
+ if (direct)
|
|
|
|
+ return fn(arg);
|
|
|
|
+ return work_on_cpu(cpu, fn, arg);
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+static int __acpi_processor_set_throttling(struct acpi_processor *pr,
|
|
|
|
+ int state, bool force, bool direct)
|
|
|
|
{
|
|
|
|
int ret = 0;
|
|
|
|
unsigned int i;
|
|
|
|
@@ -1130,7 +1133,8 @@ int acpi_processor_set_throttling(struct
|
|
|
|
arg.pr = pr;
|
|
|
|
arg.target_state = state;
|
|
|
|
arg.force = force;
|
|
|
|
- ret = work_on_cpu(pr->id, acpi_processor_throttling_fn, &arg);
|
|
|
|
+ ret = call_on_cpu(pr->id, acpi_processor_throttling_fn, &arg,
|
|
|
|
+ direct);
|
|
|
|
} else {
|
|
|
|
/*
|
|
|
|
* When the T-state coordination is SW_ALL or HW_ALL,
|
|
|
|
@@ -1163,8 +1167,8 @@ int acpi_processor_set_throttling(struct
|
|
|
|
arg.pr = match_pr;
|
|
|
|
arg.target_state = state;
|
|
|
|
arg.force = force;
|
|
|
|
- ret = work_on_cpu(pr->id, acpi_processor_throttling_fn,
|
|
|
|
- &arg);
|
|
|
|
+ ret = call_on_cpu(pr->id, acpi_processor_throttling_fn,
|
|
|
|
+ &arg, direct);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
@@ -1182,6 +1186,12 @@ int acpi_processor_set_throttling(struct
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
+int acpi_processor_set_throttling(struct acpi_processor *pr, int state,
|
|
|
|
+ bool force)
|
|
|
|
+{
|
|
|
|
+ return __acpi_processor_set_throttling(pr, state, force, false);
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
int acpi_processor_get_throttling_info(struct acpi_processor *pr)
|
|
|
|
{
|
|
|
|
int result = 0;
|