* Re: [tip:x86/urgent] x86: tsc: Prevent delayed init if initial tsc calibration failed
[not found] <tip-29fe359ca20326e57b25e8545c49ed9ff5e830c7@git.kernel.org>
@ 2011-01-11 15:46 ` John Stultz
0 siblings, 0 replies; only message in thread
From: John Stultz @ 2011-01-11 15:46 UTC (permalink / raw)
To: linux-kernel, mingo, hpa, tglx, kas; +Cc: linux-tip-commits
On Tue, 2011-01-11 at 10:51 +0000, tip-bot for Thomas Gleixner wrote:
> Commit-ID: 29fe359ca20326e57b25e8545c49ed9ff5e830c7
> Gitweb: http://git.kernel.org/tip/29fe359ca20326e57b25e8545c49ed9ff5e830c7
> Author: Thomas Gleixner <tglx@linutronix.de>
> AuthorDate: Tue, 11 Jan 2011 11:40:48 +0100
> Committer: Thomas Gleixner <tglx@linutronix.de>
> CommitDate: Tue, 11 Jan 2011 11:48:39 +0100
>
> x86: tsc: Prevent delayed init if initial tsc calibration failed
>
> commit a8760ec (x86: Check tsc available/disabled in the delayed init
> function) missed to prevent the setup of the delayed init function in
> case the initial tsc calibration failed. This results in the same
> divide by zero bug as we have seen without the tsc disabled check.
>
> Skip the delayed work setup when tsc_khz (the initial calibration
> value) is 0.
>
> Bisected-and-tested-by: Kirill A. Shutemov <kas@openvz.org>
> Cc: John Stultz <john.stultz@linaro.org>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Krill: Thanks for reporting and testing!
Thomas: Thanks for the fix. I'll see if we can't condense the invalid
states a bit more. If tsc_khz=0, we probably should set tsc_disabled.
Acked-by: John Stultz <johnstul@us.ibm.com>
> ---
> arch/x86/kernel/tsc.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
> index 356a0d4..463901e 100644
> --- a/arch/x86/kernel/tsc.c
> +++ b/arch/x86/kernel/tsc.c
> @@ -965,7 +965,7 @@ out:
>
> static int __init init_tsc_clocksource(void)
> {
> - if (!cpu_has_tsc || tsc_disabled > 0)
> + if (!cpu_has_tsc || tsc_disabled > 0 || !tsc_khz)
> return 0;
>
> if (tsc_clocksource_reliable)
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