linux-kernel - Re: [PATCH] x86/mce: fix a wrong assignment of i

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Date:   Mon, 15 Jun 2020 13:36:04 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     "Luck, Tony" <tony.luck@...el.com>
Cc:     Zhenzhong Duan <zhenzhong.duan@...il.com>,
        linux-kernel@...r.kernel.org, linux-edac@...r.kernel.org,
        x86@...nel.org, tglx@...utronix.de, mingo@...hat.com,
        hpa@...or.com, Yazen Ghannam <yazen.ghannam@....com>
Subject: Re: [PATCH] x86/mce: fix a wrong assignment of i_mce.status

On Thu, Jun 11, 2020 at 09:55:00AM -0700, Luck, Tony wrote:
> +Yazen
> 
> On Thu, Jun 11, 2020 at 10:32:38AM +0800, Zhenzhong Duan wrote:
> > The original code is a nop as i_mce.status is or'ed with part of itself,
> > fix it.
> > 
> > Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...il.com>
> > ---
> >  arch/x86/kernel/cpu/mce/inject.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
> > index 3413b41..dc28a61 100644
> > --- a/arch/x86/kernel/cpu/mce/inject.c
> > +++ b/arch/x86/kernel/cpu/mce/inject.c
> > @@ -511,7 +511,7 @@ static void do_inject(void)
> >  	 */
> >  	if (inj_type == DFR_INT_INJ) {
> >  		i_mce.status |= MCI_STATUS_DEFERRED;
> > -		i_mce.status |= (i_mce.status & ~MCI_STATUS_UC);
> > +		i_mce.status &= ~MCI_STATUS_UC;
> 
> Boris: "git blame" says you wrote this code.

Not me but I should've caught it:

a1300e505297 ("x86/ras/mce_amd_inj: Trigger deferred and thresholding errors interrupts")

:-\

I believe Aravind wanted to do the &= thing, i.e.,

	i_mce.status = (i_mce.status & ~MCI_STATUS_UC);

or the short version above.

:-)

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette