BACKPORT: PM: sleep: Fix possible deadlocks in core system-wide PM code
It is reported that in low-memory situations the system-wide resume core
code deadlocks, because async_schedule_dev() executes its argument
function synchronously if it cannot allocate memory (and not only in
that case) and that function attempts to acquire a mutex that is already
held. Executing the argument function synchronously from within
dpm_async_fn() may also be problematic for ordering reasons (it may
cause a consumer device's resume callback to be invoked before a
requisite supplier device's one, for example).
Address this by changing the code in question to use
async_schedule_dev_nocall() for scheduling the asynchronous
execution of device suspend and resume functions and to directly
run them synchronously if async_schedule_dev_nocall() returns false.
Link: https://lore.kernel.org/linux-pm/ZYvjiqX6EsL15moe@perf/
Reported-by: Youngmin Nam <youngmin.nam@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Tested-by: Youngmin Nam <youngmin.nam@samsung.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: 5.7+ <stable@vger.kernel.org> # 5.7+: 6aa09a5bccd8 async: Split async_schedule_node_domain()
Cc: 5.7+ <stable@vger.kernel.org> # 5.7+: 7d4b5d7a37bd async: Introduce async_schedule_dev_nocall()
Cc: 5.7+ <stable@vger.kernel.org> # 5.7+
Bug: 319759660
Bug: 337818651
Change-Id: I1164a6a0b9899ab2f01d5efb413827b9d0983d98
(cherry picked from commit 7839d0078e0d5e6cc2fa0b0dfbee71de74f1e557)
[Youngmin: Resolved minor conflict in drivers/base/power/main.c]
Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
(cherry picked from commit 7eedea7abfe900b1fe476324a10bd95ea60a8e8b)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 69a485f..819d911 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -580,7 +580,7 @@
}
/**
- * device_resume_noirq - Execute a "noirq resume" callback for given device.
+ * __device_resume_noirq - Execute a "noirq resume" callback for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
* @async: If true, the device is being resumed asynchronously.
@@ -588,7 +588,7 @@
* The driver of @dev will not receive interrupts while this function is being
* executed.
*/
-static int device_resume_noirq(struct device *dev, pm_message_t state, bool async)
+static void __device_resume_noirq(struct device *dev, pm_message_t state, bool async)
{
pm_callback_t callback = NULL;
const char *info = NULL;
@@ -656,7 +656,13 @@
Out:
complete_all(&dev->power.completion);
TRACE_RESUME(error);
- return error;
+
+ if (error) {
+ suspend_stats.failed_resume_noirq++;
+ dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
+ dpm_save_failed_dev(dev_name(dev));
+ pm_dev_err(dev, state, async ? " async noirq" : " noirq", error);
+ }
}
static bool is_async(struct device *dev)
@@ -669,11 +675,15 @@
{
reinit_completion(&dev->power.completion);
- if (is_async(dev)) {
- get_device(dev);
- async_schedule_dev(func, dev);
+ if (!is_async(dev))
+ return false;
+
+ get_device(dev);
+
+ if (async_schedule_dev_nocall(func, dev))
return true;
- }
+
+ put_device(dev);
return false;
}
@@ -681,15 +691,19 @@
static void async_resume_noirq(void *data, async_cookie_t cookie)
{
struct device *dev = (struct device *)data;
- int error;
- error = device_resume_noirq(dev, pm_transition, true);
- if (error)
- pm_dev_err(dev, pm_transition, " async", error);
-
+ __device_resume_noirq(dev, pm_transition, true);
put_device(dev);
}
+static void device_resume_noirq(struct device *dev)
+{
+ if (dpm_async_fn(dev, async_resume_noirq))
+ return;
+
+ __device_resume_noirq(dev, pm_transition, false);
+}
+
static void dpm_noirq_resume_devices(pm_message_t state)
{
struct device *dev;
@@ -699,14 +713,6 @@
mutex_lock(&dpm_list_mtx);
pm_transition = state;
- /*
- * Advanced the async threads upfront,
- * in case the starting of async threads is
- * delayed by non-async resuming devices.
- */
- list_for_each_entry(dev, &dpm_noirq_list, power.entry)
- dpm_async_fn(dev, async_resume_noirq);
-
while (!list_empty(&dpm_noirq_list)) {
dev = to_device(dpm_noirq_list.next);
get_device(dev);
@@ -714,17 +720,7 @@
mutex_unlock(&dpm_list_mtx);
- if (!is_async(dev)) {
- int error;
-
- error = device_resume_noirq(dev, state, false);
- if (error) {
- suspend_stats.failed_resume_noirq++;
- dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
- dpm_save_failed_dev(dev_name(dev));
- pm_dev_err(dev, state, " noirq", error);
- }
- }
+ device_resume_noirq(dev);
put_device(dev);
@@ -752,14 +748,14 @@
}
/**
- * device_resume_early - Execute an "early resume" callback for given device.
+ * __device_resume_early - Execute an "early resume" callback for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
* @async: If true, the device is being resumed asynchronously.
*
* Runtime PM is disabled for @dev while this function is being executed.
*/
-static int device_resume_early(struct device *dev, pm_message_t state, bool async)
+static void __device_resume_early(struct device *dev, pm_message_t state, bool async)
{
pm_callback_t callback = NULL;
const char *info = NULL;
@@ -812,21 +808,31 @@
pm_runtime_enable(dev);
complete_all(&dev->power.completion);
- return error;
+
+ if (error) {
+ suspend_stats.failed_resume_early++;
+ dpm_save_failed_step(SUSPEND_RESUME_EARLY);
+ dpm_save_failed_dev(dev_name(dev));
+ pm_dev_err(dev, state, async ? " async early" : " early", error);
+ }
}
static void async_resume_early(void *data, async_cookie_t cookie)
{
struct device *dev = (struct device *)data;
- int error;
- error = device_resume_early(dev, pm_transition, true);
- if (error)
- pm_dev_err(dev, pm_transition, " async", error);
-
+ __device_resume_early(dev, pm_transition, true);
put_device(dev);
}
+static void device_resume_early(struct device *dev)
+{
+ if (dpm_async_fn(dev, async_resume_early))
+ return;
+
+ __device_resume_early(dev, pm_transition, false);
+}
+
/**
* dpm_resume_early - Execute "early resume" callbacks for all devices.
* @state: PM transition of the system being carried out.
@@ -840,14 +846,6 @@
mutex_lock(&dpm_list_mtx);
pm_transition = state;
- /*
- * Advanced the async threads upfront,
- * in case the starting of async threads is
- * delayed by non-async resuming devices.
- */
- list_for_each_entry(dev, &dpm_late_early_list, power.entry)
- dpm_async_fn(dev, async_resume_early);
-
while (!list_empty(&dpm_late_early_list)) {
dev = to_device(dpm_late_early_list.next);
get_device(dev);
@@ -855,17 +853,7 @@
mutex_unlock(&dpm_list_mtx);
- if (!is_async(dev)) {
- int error;
-
- error = device_resume_early(dev, state, false);
- if (error) {
- suspend_stats.failed_resume_early++;
- dpm_save_failed_step(SUSPEND_RESUME_EARLY);
- dpm_save_failed_dev(dev_name(dev));
- pm_dev_err(dev, state, " early", error);
- }
- }
+ device_resume_early(dev);
put_device(dev);
@@ -889,12 +877,12 @@
EXPORT_SYMBOL_GPL(dpm_resume_start);
/**
- * device_resume - Execute "resume" callbacks for given device.
+ * __device_resume - Execute "resume" callbacks for given device.
* @dev: Device to handle.
* @state: PM transition of the system being carried out.
* @async: If true, the device is being resumed asynchronously.
*/
-static int device_resume(struct device *dev, pm_message_t state, bool async)
+static void __device_resume(struct device *dev, pm_message_t state, bool async)
{
pm_callback_t callback = NULL;
const char *info = NULL;
@@ -976,20 +964,30 @@
TRACE_RESUME(error);
- return error;
+ if (error) {
+ suspend_stats.failed_resume++;
+ dpm_save_failed_step(SUSPEND_RESUME);
+ dpm_save_failed_dev(dev_name(dev));
+ pm_dev_err(dev, state, async ? " async" : "", error);
+ }
}
static void async_resume(void *data, async_cookie_t cookie)
{
struct device *dev = (struct device *)data;
- int error;
- error = device_resume(dev, pm_transition, true);
- if (error)
- pm_dev_err(dev, pm_transition, " async", error);
+ __device_resume(dev, pm_transition, true);
put_device(dev);
}
+static void device_resume(struct device *dev)
+{
+ if (dpm_async_fn(dev, async_resume))
+ return;
+
+ __device_resume(dev, pm_transition, false);
+}
+
/**
* dpm_resume - Execute "resume" callbacks for non-sysdev devices.
* @state: PM transition of the system being carried out.
@@ -1009,27 +1007,17 @@
pm_transition = state;
async_error = 0;
- list_for_each_entry(dev, &dpm_suspended_list, power.entry)
- dpm_async_fn(dev, async_resume);
-
while (!list_empty(&dpm_suspended_list)) {
dev = to_device(dpm_suspended_list.next);
+
get_device(dev);
- if (!is_async(dev)) {
- int error;
- mutex_unlock(&dpm_list_mtx);
+ mutex_unlock(&dpm_list_mtx);
- error = device_resume(dev, state, false);
- if (error) {
- suspend_stats.failed_resume++;
- dpm_save_failed_step(SUSPEND_RESUME);
- dpm_save_failed_dev(dev_name(dev));
- pm_dev_err(dev, state, "", error);
- }
+ device_resume(dev);
- mutex_lock(&dpm_list_mtx);
- }
+ mutex_lock(&dpm_list_mtx);
+
if (!list_empty(&dev->power.entry))
list_move_tail(&dev->power.entry, &dpm_prepared_list);
