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From:   Thomas Gleixner <tglx@linutronix.de>
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To:     maninder1.s@samsung.com, "fweisbec@gmail.com" <fweisbec@gmail.com>,
        "mingo@kernel.org" <mingo@kernel.org>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Vaneet Narang <v.narang@samsung.com>,
        AMIT SAHRAWAT <a.sahrawat@samsung.com>,
        Chung-Ki Woo <chungki0201.woo@samsung.com>
Subject: Re: [Issue] timer callback registered with mod_timer is getting
 called beforetime
In-Reply-To: <20210924065310epcms5p69dd47a510faaa6bf68c243e02f2d0186@epcms5p6>
References: <CGME20210924065310epcms5p69dd47a510faaa6bf68c243e02f2d0186@epcms5p6>
 <20210924065310epcms5p69dd47a510faaa6bf68c243e02f2d0186@epcms5p6>
Date:   Fri, 24 Sep 2021 14:08:50 +0200
Message-ID: <87mto2dvl9.ffs@tglx>
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On Fri, Sep 24 2021 at 12:23, Maninder Singh wrote:
?
> As we checekd code if CPU responsible for updating jiffies value(lets
> say CPU0) has interrupts disabled for 60 ms and in mean time other
> CPU(CPU1) registers new timer for (jiffies + x) value. its callback
> will be called before time.

So you run some stuff for 60ms with interrupts disabled and now you are
asking what's wrong?

The answer is simply: Keeping interrupts disabled for 60ms is wrong.

Anything else is just a symptom.

Thanks,

        tglx