On 2017-05-26 19:16:07 [+0200], Anna-Maria Gleixner wrote:

This reverts commit 032f93cae150a.

The problem is that the look ahead optimization from the tick timer
interrupt context can race with the softirq thread expiring timer. As
a consequence the temporary hlist heads which hold the to expire
timers are overwritten and the timers which are already removed from
the wheel bucket for expiry are now dangling w/o a list head.

That means those timers never get expired. If one of those timers is
canceled the removal operation will result in a hlist corruption.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>

Applied

Sebastian