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PM / hibernate: Restore processor state before using per-CPU variables

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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: bb3632c610 (PM / sleep: trace events for suspend/resume)
Reported-and-tested-by: Borislav Petkov <bp@suse.de>
Reported-by: Jiri Kosina <jikos@kernel.org>
Tested-by: Rafael J. Wysocki <rafael@kernel.org>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Thomas Garnier 2016-08-11 14:49:29 -07:00 committed by Rafael J. Wysocki
parent e4630fdd47
commit 62822e2ec4
1 changed files with 2 additions and 2 deletions
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4
kernel/power/hibernate.c
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@ -300,12 +300,12 @@ static int create_image(int platform_mode)
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;