4.7-stable review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Garnier <[email protected]> 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 <[email protected]> Reported-by: Jiri Kosina <[email protected]> Tested-by: Rafael J. Wysocki <[email protected]> Tested-by: Jiri Kosina <[email protected]> Signed-off-by: Thomas Garnier <[email protected]> Acked-by: Pavel Machek <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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;
