ftrace: Disable function tracing during suspend/resume and hibernation, again
If function tracing is enabled for some of the low-level suspend/resume
functions, it leads to triple fault during resume from suspend, ultimately
ending up in a reboot instead of a resume (or a total refusal to come out
of suspended state, on some machines).
This issue was explained in more detail in commit f42ac38c59e0a03d (ftrace:
disable tracing for suspend to ram). However, the changes made by that commit
got reverted by commit cbe2f5a6e84eebb (tracing: allow tracing of
suspend/resume & hibernation code again). So, unfortunately since things are
not yet robust enough to allow tracing of low-level suspend/resume functions,
suspend/resume is still broken when ftrace is enabled.
So fix this by disabling function tracing during suspend/resume & hibernation.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 21ad3fe..0d4b354 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -358,6 +358,7 @@
}
suspend_console();
+ ftrace_stop();
pm_restrict_gfp_mask();
error = dpm_suspend(PMSG_FREEZE);
@@ -383,6 +384,7 @@
if (error || !in_suspend)
pm_restore_gfp_mask();
+ ftrace_start();
resume_console();
dpm_complete(msg);
@@ -485,6 +487,7 @@
pm_prepare_console();
suspend_console();
+ ftrace_stop();
pm_restrict_gfp_mask();
error = dpm_suspend_start(PMSG_QUIESCE);
if (!error) {
@@ -492,6 +495,7 @@
dpm_resume_end(PMSG_RECOVER);
}
pm_restore_gfp_mask();
+ ftrace_start();
resume_console();
pm_restore_console();
return error;
@@ -518,6 +522,7 @@
entering_platform_hibernation = true;
suspend_console();
+ ftrace_stop();
error = dpm_suspend_start(PMSG_HIBERNATE);
if (error) {
if (hibernation_ops->recover)
@@ -561,6 +566,7 @@
Resume_devices:
entering_platform_hibernation = false;
dpm_resume_end(PMSG_RESTORE);
+ ftrace_start();
resume_console();
Close:
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 396d262..c8b7446 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -24,6 +24,7 @@
#include <linux/export.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
+#include <linux/ftrace.h>
#include <trace/events/power.h>
#include "power.h"
@@ -212,6 +213,7 @@
goto Close;
}
suspend_console();
+ ftrace_stop();
suspend_test_start();
error = dpm_suspend_start(PMSG_SUSPEND);
if (error) {
@@ -231,6 +233,7 @@
suspend_test_start();
dpm_resume_end(PMSG_RESUME);
suspend_test_finish("resume devices");
+ ftrace_start();
resume_console();
Close:
if (suspend_ops->end)
