Re: [PATCH 3/3] perf: Fix mux_interval hrtimer wreckage

From: David Ahern
Date: Wed Apr 15 2015 - 09:48:17 EST


Hi Peter:

On 4/15/15 3:41 AM, Peter Zijlstra wrote:
Thomas stumbled over the hrtimer_forward_now() in
perf_event_mux_interval_ms_store() and noticed its broken-ness.

You cannot just change the expiry time of an active timer, it will
destroy the red-black tree order and cause havoc.

Change it to (re)start the timer instead, (re)starting a timer will
dequeue and enqueue a timer and therefore preserve rb-tree order.

Should this be fixed in stable trees as well?

David
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