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From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	diego.viola@gmail.com, len.brown@intel.com, rjw@rjwysocki.net,
	rui.zhang@intel.com, stable@kernel.org
Subject: [PATCH v2 1/7] x86,tsc: Always unregister clocksource_tsc_early
Date: Mon, 30 Apr 2018 12:00:09 +0200	[thread overview]
Message-ID: <20180430100344.350507853@infradead.org> (raw)
In-Reply-To: <20180430100008.503783478@infradead.org>

[-- Attachment #1: peterz-tsc-early-fix-1.patch --]
[-- Type: text/plain, Size: 1768 bytes --]

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: aa83c45762a2 ("x86/tsc: Introduce early tsc clocksource")
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 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
@@ -1244,7 +1244,7 @@ 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
@@ -1297,11 +1297,12 @@ 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);
 }
 
@@ -1311,8 +1312,8 @@ 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;
@@ -1328,6 +1329,7 @@ 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;
 	}

  reply	other threads:[~2018-04-30 10:04 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-30 10:00 [PATCH v2 0/7] Various tsc/clocksource fixes Peter Zijlstra
2018-04-30 10:00 ` Peter Zijlstra [this message]
2018-05-02 14:12   ` [tip:timers/urgent] x86/tsc: Always unregister clocksource_tsc_early tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 2/7] clocksource: Allow clocksource_mark_unstable() on unregisered clocksources Peter Zijlstra
2018-05-02 13:35   ` Thomas Gleixner
2018-05-02 13:53     ` Peter Zijlstra
2018-05-02 14:13       ` [tip:timers/urgent] clocksource: Allow clocksource_mark_unstable() on unregistered clocksources tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 3/7] clocksource: Initialize cs->wd_list Peter Zijlstra
2018-05-02 13:37   ` Thomas Gleixner
2018-05-02 13:55     ` Peter Zijlstra
2018-05-02 14:13   ` [tip:timers/urgent] " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 4/7] x86,tsc: Fix mark_tsc_unstable() Peter Zijlstra
2018-05-02 14:14   ` [tip:timers/urgent] x86/tsc: " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 5/7] clocksource: Consistent de-rate when marking unstable Peter Zijlstra
2018-05-02 14:14   ` [tip:timers/urgent] " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 6/7] clocksource: Rework stale comment Peter Zijlstra
2018-05-02 14:15   ` [tip:timers/urgent] " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 7/7] clocksource: Remove kthread Peter Zijlstra
2018-05-02 14:42   ` [tip:timers/core] " tip-bot for Peter Zijlstra
2018-05-01  9:12 ` [PATCH v2 0/7] Various tsc/clocksource fixes Rafael J. Wysocki

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