From: Thomas Garnier Date: Thu, 11 Aug 2016 21:49:29 +0000 (-0700) Subject: PM / hibernate: Restore processor state before using per-CPU variables X-Git-Tag: firefly_0821_release~176^2~4^2~27^2~6 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=119c348a8ef2765fb19c96f76480d4aaefdcae23;p=firefly-linux-kernel-4.4.55.git PM / hibernate: Restore processor state before using per-CPU variables 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 Reported-by: Jiri Kosina Tested-by: Rafael J. Wysocki Tested-by: Jiri Kosina Signed-off-by: Thomas Garnier Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index b7dd5718836e..3124cebaec31 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -299,12 +299,12 @@ 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;