This is a note to let you know that I've just added the patch titled
PM: sleep: Fix possible deadlocks in core system-wide PM code
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pm-sleep-fix-possible-deadlocks-in-core-system-wide-.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c396cc5821d1d3b5d9fb188e7de296ba34803b18
Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Date: Wed Dec 27 21:41:06 2023 +0100
PM: sleep: Fix possible deadlocks in core system-wide PM code
[ Upstream commit 7839d0078e0d5e6cc2fa0b0dfbee71de74f1e557 ]
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@xxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@xxxxxxxxxxxxxxx>
Tested-by: Youngmin Nam <youngmin.nam@xxxxxxxxxxx>
Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Cc: 5.7+ <stable@xxxxxxxxxxxxxxx> # 5.7+: 6aa09a5bccd8 async: Split async_schedule_node_domain()
Cc: 5.7+ <stable@xxxxxxxxxxxxxxx> # 5.7+: 7d4b5d7a37bd async: Introduce async_schedule_dev_nocall()
Cc: 5.7+ <stable@xxxxxxxxxxxxxxx> # 5.7+
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 402f3c4e3668..c493e48e420f 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -583,7 +583,7 @@ bool dev_pm_skip_resume(struct device *dev)
}
/**
- * 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.
@@ -591,7 +591,7 @@ bool dev_pm_skip_resume(struct device *dev)
* 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;
@@ -659,7 +659,13 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
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)
@@ -672,11 +678,15 @@ static bool dpm_async_fn(struct device *dev, async_func_t func)
{
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;
}
@@ -684,15 +694,19 @@ static bool dpm_async_fn(struct device *dev, async_func_t func)
static void async_resume_noirq(void *data, async_cookie_t cookie)
{
struct device *dev = 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;
@@ -702,14 +716,6 @@ static void dpm_noirq_resume_devices(pm_message_t state)
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);
@@ -717,17 +723,7 @@ static void dpm_noirq_resume_devices(pm_message_t state)
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);
@@ -757,14 +753,14 @@ void dpm_resume_noirq(pm_message_t state)
}
/**
- * 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;
@@ -817,21 +813,31 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
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 = 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.
@@ -845,14 +851,6 @@ void dpm_resume_early(pm_message_t state)
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);
@@ -860,17 +858,7 @@ void dpm_resume_early(pm_message_t state)
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);
@@ -894,12 +882,12 @@ void dpm_resume_start(pm_message_t state)
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;
@@ -981,20 +969,30 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
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 = 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.
@@ -1014,27 +1012,17 @@ void dpm_resume(pm_message_t state)
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);
+
+ device_resume(dev);
- 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);
- }
+ 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);
