Re: [PATCH 4/7] [hrtimers] Fix posix-timer requeue race

[Roman Zippel]

Hi,

On Fri, 20 Jan 2006, Thomas Gleixner wrote:

> CPU0 expires a posix-timer and runs the callback function.
> The signal is queued.
> After releasing the posix-timer lock and before returning to
> hrtimer_run_queue CPU0 gets interrupted.
> CPU1 delivers the queued signal and rearms the timer.
> CPU0 comes back to hrtimer_run_queue and sets the timer state to expired.
> The next modification of the timer can result in an oops, because the state
> information is wrong.

Thomas, this is exactly what I meant with overloaded state machines,
enumerated states are very hard to get right with concurrent processes.
Please get rid of the state field and at least use a flag field instead.

bye, Roman
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