Re: Soft lockup issue in Linux 4.1.9

From: Thomas Gleixner
Date: Fri Oct 02 2015 - 17:05:21 EST


On Fri, 2 Oct 2015, Eric Dumazet wrote:
> On Fri, 2015-10-02 at 22:04 +0200, Thomas Gleixner wrote:
>
> > What makes sure, that the timer cannot be readded while that timer
> > callback is running?
>
> What is exactly your question ?

CPU0 CPU1

timer expires
callback
add timer
timer_pending() == true
===> del_timer_sync()

I was just curious how this is prevented as I got lost in the
networking code as usual :)

Thanks,

tglx

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