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Subjectkernel/posix-timer.c: Forgot to disable interrupts in sys_timer_settime()?
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Hi,

Did we forget to disable interrupts before calling
posix_cpu_timer_set() in the system call function sys_timer_settime()
(in code literally as SYSCALL_DEFINE4(timer_settime, ...) as shown
below)? The CLOCK_DISPATCH macro invokes posix_cpu_timer_set(), which
requires interrupts to be disabled upon entry of calling. When
posix_cpu_timer_set() was called from other functions such as
do_cpu_nanosleep(), interrupts are disabled.


SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
769 const struct itimerspec __user *, new_setting,
770 struct itimerspec __user *, old_setting)
771{
...
792 error = CLOCK_DISPATCH(timr->it_clock, timer_set,
793 (timr, flags, &new_spec, rtn)); //
this MACRO invokes posix_cpu_timer_set()
...
}


In addition, its block comments also state that we must disable
interrupts before calling it (in posix-cpu-timers.c):

/*
712 * ...
713 * This is called with the timer locked and interrupts disabled.
714 *
...
716 */
717int posix_cpu_timer_set(struct k_itimer *timer, int flags,
718 struct itimerspec *new, struct itimerspec *old)
719{
...
}

Thanks,
Lin


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