x86/tsc: Always unregister clocksource_tsc_early (e9088add) · Commits · 戴 / test

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:

Diego Viola <diego.viola@gmail.com> Fixes: ("x86/tsc: Introduce early tsc clocksource") Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Reviewed-by:

Rafael 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

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;
		}

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