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    Subject[PATCH] posix-timers: CLOCK_MONOTONIC_RAW: fix the usage of ->it_clock
    (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;
    }

    +static int common_timer_create(struct k_itimer *new_timer)
    +{
    + return __common_timer_init(new_timer, HRTIMER_MODE_ABS);
    +}
    +
    /*
    * Return nonzero if we know a priori this clockid_t value is bogus.
    */
    @@ -730,7 +738,7 @@ common_timer_set(struct k_itimer *timr,
    return 0;

    mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
    - hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
    + __common_timer_init(timr, mode);
    timr->it.real.timer.function = posix_timer_fn;

    hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));


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