This is a note to let you know that I've just added the patch titled
PM / hibernate: Restore processor state before using per-CPU variables
to the 4.4-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-hibernate-restore-processor-state-before-using-per-cpu-variables.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 62822e2ec4ad091ba31f823f577ef80db52e3c2c Mon Sep 17 00:00:00 2001
From: Thomas Garnier <thgarnie@xxxxxxxxxx>
Date: Thu, 11 Aug 2016 14:49:29 -0700
Subject: PM / hibernate: Restore processor state before using per-CPU variables
From: Thomas Garnier <thgarnie@xxxxxxxxxx>
commit 62822e2ec4ad091ba31f823f577ef80db52e3c2c upstream.
Restore the processor state before calling any other functions to
ensure per-CPU variables can be used with KASLR memory randomization.
Tracing functions use per-CPU variables (GS based on x86) and one was
called just before restoring the processor state fully. It resulted
in a double fault when both the tracing & the exception handler
functions tried to use a per-CPU variable.
Fixes: bb3632c6101b (PM / sleep: trace events for suspend/resume)
Reported-and-tested-by: Borislav Petkov <bp@xxxxxxx>
Reported-by: Jiri Kosina <jikos@xxxxxxxxxx>
Tested-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>
Tested-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Thomas Garnier <thgarnie@xxxxxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/power/hibernate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -299,12 +299,12 @@ static int create_image(int platform_mod
save_processor_state();
trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
error = swsusp_arch_suspend();
+ /* Restore control flow magically appears here */
+ restore_processor_state();
trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
if (error)
printk(KERN_ERR "PM: Error %d creating hibernation image\n",
error);
- /* Restore control flow magically appears here */
- restore_processor_state();
if (!in_suspend)
events_check_enabled = false;
Patches currently in stable-queue which might be from thgarnie@xxxxxxxxxx are
queue-4.4/pm-hibernate-restore-processor-state-before-using-per-cpu-variables.patch
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