From: Greg KH <gregkh@linuxfoundation.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: John Crispin <john@phrozen.org>,
frederic@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Anna-Maria Gleixner <anna-maria@linutronix.de>,
Thomas Gleixner <tglx@linutronix.de>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH stable] tick/nohz: Prevent bogus softirq pending warning
Date: Thu, 27 Sep 2018 10:48:17 +0200 [thread overview]
Message-ID: <20180927084817.GA10781@kroah.com> (raw)
In-Reply-To: <CAMuHMdXyAQP_GYyHXJd7qq1ww25TbVs5QONDTqzLK_arGiLeMQ@mail.gmail.com>
On Thu, Sep 27, 2018 at 10:07:39AM +0200, Geert Uytterhoeven wrote:
> Hi Greg,
>
> On Wed, Sep 12, 2018 at 3:56 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Thu, Aug 30, 2018 at 5:06 PM Thomas Gleixner <tglx@linutronix.de> wrote:
> > > Commit 0a0e0829f990 ("nohz: Fix missing tick reprogram when interrupting an
> > > inline softirq") got backported to stable trees and now causes the NOHZ
> > > softirq pending warning to trigger. It's not an upstream issue as the NOHZ
> > > update logic has been changed there.
> > >
> > > The problem is when a softirq disabled section gets interrupted and on
> > > return from interrupt the tick/nohz state is evaluated, which then can
> > > observe pending soft interrupts. These soft interrupts are legitimately
> > > pending because they cannot be processed as long as soft interrupts are
> > > disabled and the interrupted code will correctly process them when soft
> > > interrupts are reenabled.
> > >
> > > Add a check for softirqs disabled to the pending check to prevent the
> > > warning.
> > >
> > > Reported-by: Grygorii Strashko <grygorii.strashko@ti.com>
> > > Reported-by: John Crispin <john@phrozen.org>
> > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> > > Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
> > > Tested-by: John Crispin <john@phrozen.org>
> > > Cc: Frederic Weisbecker <frederic@kernel.org>
> > > Cc: Ingo Molnar <mingo@kernel.org>
> > > Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > Cc: stable@vger.kernel.org
> >
> > Fixes: 2d898915ccf4838c ("nohz: Fix missing tick reprogram when
> > interrupting an inline softirq")
> >
> > Issue in v4.14.x bisected to the above commit, and fixed by your patch.
> >
> > Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> This issue is still present in v4.14.72. Can you please apply Thomas' fix?
Oops, sorry for the delay, now queued up.
greg k-h
prev parent reply other threads:[~2018-09-27 15:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-30 15:05 [PATCH stable] tick/nohz: Prevent bogus softirq pending warning Thomas Gleixner
2018-08-30 15:12 ` Frederic Weisbecker
2018-09-12 13:56 ` Geert Uytterhoeven
2018-09-27 8:07 ` Geert Uytterhoeven
2018-09-27 8:48 ` Greg KH [this message]
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