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    SubjectRe: [PATCH] posix-timers: CLOCK_MONOTONIC_RAW: fix the usage of ->it_clock
    On Sat, 20 Dec 2008, Oleg Nesterov wrote:

    > (compile tested)
    >
    > common_timer_create() and common_timer_set() blindly pass ->it_clock to
    > hrtimer_init() as clock_id. This used to work until CLOCK_MONOTONIC_RAW
    > was introduced, now we should be careful.
    >
    > Perhaps it makes sense to add BUG_ON(clock_id >= HRTIMER_MAX_CLOCK_BASES)
    > to __hrtimer_init(), the wrong clock_id leads to catastrophe.
    >
    > Reported-by: Eric Sesterhenn <snakebyte@gmx.de>
    > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    >
    > --- K-28/kernel/posix-timers.c~CLOCK_MONOTONIC_RAW 2008-12-02 17:12:40.000000000 +0100
    > +++ K-28/kernel/posix-timers.c 2008-12-20 18:23:28.000000000 +0100
    > @@ -191,12 +191,20 @@ static inline int common_clock_set(const
    > return do_sys_settimeofday(tp, NULL);
    > }
    >
    > -static int common_timer_create(struct k_itimer *new_timer)
    > +static inline int
    > +__common_timer_init(struct k_itimer *timer, enum hrtimer_mode mode)
    > {
    > - hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
    > + clockid_t clock_id = timer->it_clock ?
    > + CLOCK_MONOTONIC : CLOCK_REALTIME;
    > + hrtimer_init(&timer->it.real.timer, clock_id, mode);
    > return 0;
    > }

    No, this is wrong. We do not want to create a timer for
    CLOCK_MONOTONIC_RAW.

    tglx


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