Commit 443772d4 authored by Srivatsa S. Bhat's avatar Srivatsa S. Bhat Committed by Rafael J. Wysocki
Browse files

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 f42ac38c (ftrace:
disable tracing for suspend to ram). However, the changes made by that commit
got reverted by commit cbe2f5a6 (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: default avatarSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 62c552cc

kernel/power/hibernate.c

+6 −0
Original line number Diff line number Diff line
@@ -358,6 +358,7 @@ int hibernation_snapshot(int platform_mode) 
	}



	suspend_console();

	ftrace_stop();

	pm_restrict_gfp_mask();



	error = dpm_suspend(PMSG_FREEZE);
@@ -383,6 +384,7 @@ int hibernation_snapshot(int platform_mode) 
	if (error || !in_suspend)

		pm_restore_gfp_mask();



	ftrace_start();

	resume_console();

	dpm_complete(msg);
@@ -485,6 +487,7 @@ int hibernation_restore(int platform_mode) 


	pm_prepare_console();

	suspend_console();

	ftrace_stop();

	pm_restrict_gfp_mask();

	error = dpm_suspend_start(PMSG_QUIESCE);

	if (!error) {
@@ -492,6 +495,7 @@ int hibernation_restore(int platform_mode) 
		dpm_resume_end(PMSG_RECOVER);

	}

	pm_restore_gfp_mask();

	ftrace_start();

	resume_console();

	pm_restore_console();

	return error;
@@ -518,6 +522,7 @@ int hibernation_platform_enter(void) 


	entering_platform_hibernation = true;

	suspend_console();

	ftrace_stop();

	error = dpm_suspend_start(PMSG_HIBERNATE);

	if (error) {

		if (hibernation_ops->recover)
@@ -561,6 +566,7 @@ int hibernation_platform_enter(void) 
 Resume_devices:

	entering_platform_hibernation = false;

	dpm_resume_end(PMSG_RESTORE);

	ftrace_start();

	resume_console();



 Close:

kernel/power/suspend.c

+3 −0
Original line number Diff line number Diff line
@@ -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 @@ int suspend_devices_and_enter(suspend_state_t state) 
			goto Close;

	}

	suspend_console();

	ftrace_stop();

	suspend_test_start();

	error = dpm_suspend_start(PMSG_SUSPEND);

	if (error) {
@@ -231,6 +233,7 @@ int suspend_devices_and_enter(suspend_state_t state) 
	suspend_test_start();

	dpm_resume_end(PMSG_RESUME);

	suspend_test_finish("resume devices");

	ftrace_start();

	resume_console();

 Close:

	if (suspend_ops->end)

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