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SubjectRe: [PATCH] NTP: remove clock_was_set() call to prevent deadlock

* Thomas Gleixner <> 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:
> 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 <>

looks good to me.

Acked-by: Ingo Molnar <>

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