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Commit 119c348a authored by Thomas Garnier's avatar Thomas Garnier Committed by Greg Kroah-Hartman
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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: bb3632c6 (PM / sleep: trace events for suspend/resume)
Reported-and-tested-by: default avatarBorislav Petkov <bp@suse.de>
Reported-by: default avatarJiri Kosina <jikos@kernel.org>
Tested-by: default avatarRafael J. Wysocki <rafael@kernel.org>
Tested-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarThomas Garnier <thgarnie@google.com>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent da40055e

kernel/power/hibernate.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -299,12 +299,12 @@ static int create_image(int platform_mode) 
	save_processor_state();

	save_processor_state();

	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);

	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);

	error = swsusp_arch_suspend();

	error = swsusp_arch_suspend();

	/* Restore control flow magically appears here */

	restore_processor_state();

	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);

	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);

	if (error)

	if (error)

		printk(KERN_ERR "PM: Error %d creating hibernation image\n",

		printk(KERN_ERR "PM: Error %d creating hibernation image\n",

			error);

			error);

	/* Restore control flow magically appears here */

	restore_processor_state();

	if (!in_suspend)

	if (!in_suspend)

		events_check_enabled = false;

		events_check_enabled = false;