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authorVitaly Kuznetsov <vkuznets@redhat.com>2018-10-17 14:23:55 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-10-25 19:45:08 +0300
commita1c6ca3c6de763459a6e93b644ec6518c890ba1c (patch)
tree8583841917c0b636ea25a621946126cb0228b279 /kernel/hung_task.c
parentbd6bf7c10484f026505814b690104cdef27ed460 (diff)
downloadlinux-a1c6ca3c6de763459a6e93b644ec6518c890ba1c.tar.xz
kernel: hung_task.c: disable on suspend
It is possible to observe hung_task complaints when system goes to suspend-to-idle state: # echo freeze > /sys/power/state PM: Syncing filesystems ... done. Freezing user space processes ... (elapsed 0.001 seconds) done. OOM killer disabled. Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done. sd 0:0:0:0: [sda] Synchronizing SCSI cache INFO: task bash:1569 blocked for more than 120 seconds. Not tainted 4.19.0-rc3_+ #687 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. bash D 0 1569 604 0x00000000 Call Trace: ? __schedule+0x1fe/0x7e0 schedule+0x28/0x80 suspend_devices_and_enter+0x4ac/0x750 pm_suspend+0x2c0/0x310 Register a PM notifier to disable the detector on suspend and re-enable back on wakeup. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/hung_task.c')
-rw-r--r--kernel/hung_task.c30
1 files changed, 29 insertions, 1 deletions
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index b9132d1269ef..cb8e3e8ac7b9 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -15,6 +15,7 @@
#include <linux/lockdep.h>
#include <linux/export.h>
#include <linux/sysctl.h>
+#include <linux/suspend.h>
#include <linux/utsname.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
@@ -242,6 +243,28 @@ void reset_hung_task_detector(void)
}
EXPORT_SYMBOL_GPL(reset_hung_task_detector);
+static bool hung_detector_suspended;
+
+static int hungtask_pm_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ switch (action) {
+ case PM_SUSPEND_PREPARE:
+ case PM_HIBERNATION_PREPARE:
+ case PM_RESTORE_PREPARE:
+ hung_detector_suspended = true;
+ break;
+ case PM_POST_SUSPEND:
+ case PM_POST_HIBERNATION:
+ case PM_POST_RESTORE:
+ hung_detector_suspended = false;
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
/*
* kthread which checks for tasks stuck in D state
*/
@@ -261,7 +284,8 @@ static int watchdog(void *dummy)
interval = min_t(unsigned long, interval, timeout);
t = hung_timeout_jiffies(hung_last_checked, interval);
if (t <= 0) {
- if (!atomic_xchg(&reset_hung_task, 0))
+ if (!atomic_xchg(&reset_hung_task, 0) &&
+ !hung_detector_suspended)
check_hung_uninterruptible_tasks(timeout);
hung_last_checked = jiffies;
continue;
@@ -275,6 +299,10 @@ static int watchdog(void *dummy)
static int __init hung_task_init(void)
{
atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+
+ /* Disable hung task detector on suspend */
+ pm_notifier(hungtask_pm_notify, 0);
+
watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");
return 0;