Messages in this thread | | | Date | Tue, 3 Jul 2007 21:41:06 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] NTP: remove clock_was_set() call to prevent deadlock |
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* Thomas Gleixner <tglx@linutronix.de> 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() > > The only possible side effect of the removal might be, that an > absolute CLOCK_REALTIME timer fires 1 second too late, in the rare > case of leap second deletion and an absolute CLOCK_REALTIME timer > which expires in the affected time frame. It will never fire too > early. > > This was probably observed by the reporter of a June 30th -> July 1st > hang: http://lkml.org/lkml/2007/7/3/ > > A similar problem was observed by Dave Jones, who provided a screen > shot with a lockdep back trace, which allowed to analyse the problem. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
looks good to me.
Acked-by: Ingo Molnar <mingo@elte.hu>
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