4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Garnier <thgar...@google.com>
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 <b...@suse.de>
Reported-by: Jiri Kosina <ji...@kernel.org>
Tested-by: Rafael J. Wysocki <raf...@kernel.org>
Tested-by: Jiri Kosina <jkos...@suse.cz>
Signed-off-by: Thomas Garnier <thgar...@google.com>
Acked-by: Pavel Machek <pa...@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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;
