Re: [2.6.20.16 review 27/28] NTP: remove clock_was_set() call to prevent deadlock

From: Willy Tarreau
Date: Sun Aug 12 2007 - 07:49:59 EST


On Sun, Aug 12, 2007 at 04:15:58AM -0700, Jason Uhlenkott wrote:
> On Sat, Aug 11, 2007 at 21:48:19 +0200, Willy Tarreau wrote:
> > The clock_was_set() call in seconds_overflow() which happens only when
> > leap seconds are inserted / deleted is wrong in two aspects:
> >
> > 1. it results in a call to on_each_cpu() with interrupts disabled
> > 2. it is potential deadlock source vs. call_lock in smp_call_function()
>
> clock_was_set() is a no-op in 2.6.20, so this one looks unnecessary
> (but harmless). Thankfully the "hang every Linux box on the planet
> simultaneously" regression (okay, that's *slight* hyperbole) was
> limited to 2.6.21.

OK, patch removed.

Thanks for your help,
Willy

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