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Commit e9088add authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner
Browse files

x86/tsc: Always unregister clocksource_tsc_early 



Don't leave the tsc-early clocksource registered if it errors out
early.

This was reported by Diego, who on his Core2 era machine got TSC
invalidated while it was running with tsc-early (due to C-states).
This results in keeping tsc-early with very bad effects.

Reported-and-Tested-by: default avatarDiego Viola <diego.viola@gmail.com>
Fixes: aa83c457 ("x86/tsc: Introduce early tsc clocksource")
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180430100344.350507853@infradead.org
parent 6da6c0db

arch/x86/kernel/tsc.c

+6 −4
Original line number Diff line number Diff line
@@ -1244,7 +1244,7 @@ static void tsc_refine_calibration_work(struct work_struct *work) 


	/* Don't bother refining TSC on unstable systems */

	if (tsc_unstable)

		return;

		goto unreg;



	/*

	 * Since the work is started early in boot, we may be
@@ -1297,11 +1297,12 @@ static void tsc_refine_calibration_work(struct work_struct *work) 


out:

	if (tsc_unstable)

		return;

		goto unreg;



	if (boot_cpu_has(X86_FEATURE_ART))

		art_related_clocksource = &clocksource_tsc;

	clocksource_register_khz(&clocksource_tsc, tsc_khz);

unreg:

	clocksource_unregister(&clocksource_tsc_early);

}
@@ -1311,8 +1312,8 @@ static int __init init_tsc_clocksource(void) 
	if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_disabled > 0 || !tsc_khz)

		return 0;



	if (check_tsc_unstable())

		return 0;

	if (tsc_unstable)

		goto unreg;



	if (tsc_clocksource_reliable)

		clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
@@ -1328,6 +1329,7 @@ static int __init init_tsc_clocksource(void) 
		if (boot_cpu_has(X86_FEATURE_ART))

			art_related_clocksource = &clocksource_tsc;

		clocksource_register_khz(&clocksource_tsc, tsc_khz);

unreg:

		clocksource_unregister(&clocksource_tsc_early);

		return 0;

	}