4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit e9088adda13cd23249d4b0abb97ff8a81bf5573a upstream.
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@xxxxxxxxx>
Fixes: aa83c45762a2 ("x86/tsc: Introduce early tsc clocksource")
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: len.brown@xxxxxxxxx
Cc: rjw@xxxxxxxxxxxxx
Cc: diego.viola@xxxxxxxxx
Cc: rui.zhang@xxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20180430100344.350507853@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/tsc.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1205,7 +1205,7 @@ static void tsc_refine_calibration_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
@@ -1258,11 +1258,12 @@ static void tsc_refine_calibration_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);
}
@@ -1272,8 +1273,8 @@ static int __init init_tsc_clocksource(v
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;
@@ -1289,6 +1290,7 @@ static int __init init_tsc_clocksource(v
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;
}
