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From:   Marco Elver <elver@google.com>
Date:   Fri, 21 Aug 2020 09:05:46 +0200
Message-ID: <CANpmjNOnopd8usQJk0Y1mxSNrQ15e0GboNfwop4qUDCwMnQQZQ@mail.gmail.com>
Subject: Re: [PATCH 0/9] TRACE_IRQFLAGS wreckage
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>, Will Deacon <will@kernel.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>,
        "Paul E. McKenney" <paulmck@kernel.org>, rjw@rjwysocki.net,
        Joel Fernandes <joel@joelfernandes.org>, svens@linux.ibm.com,
        Thomas Gleixner <tglx@linutronix.de>
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On Fri, 21 Aug 2020 at 08:54, <peterz@infradead.org> wrote:
>
> On Thu, Aug 20, 2020 at 07:20:46PM +0200, Marco Elver wrote:
> > From 4ec9dd472c978e1eba622fb22bc04e4357f10421 Mon Sep 17 00:00:00 2001
> > From: Marco Elver <elver@google.com>
> > Date: Thu, 20 Aug 2020 19:06:09 +0200
> > Subject: [PATCH] sched: Turn inline into __always_inline due to noinstr use
> >
> > is_idle_task() may be used from noinstr functions such as
> > irqentry_enter(). Since the compiler is free to not inline regular
> > inline functions, switch to using __always_inline.
> >
> > Signed-off-by: Marco Elver <elver@google.com>
>
> Fair enough I suppose; didn't that generate an objtool warning on your
> build? (of course that requires PARAVIRT=n, I should get back to fixing
> that)

It does now after turning on VMLINUX_VALIDATION.

Although note that this patch (and the other, which I'll send
separately) wasn't required after the rcuidle fix. I suppose there is
still a small chance things can go wrong though, but syzkaller wasn't
able to find such a case (yet).

Thanks,
-- Marco