> > The condition for no context in do_exception checks for hard and
> > soft interrupts by using in_interrupt() but not for preemption.
> > This is bad for the users of __copy_from/to_user_inatomic because
> > the fault handler might call schedule although the preemption
> > count is != 0. Use in_atomic() instead in_interrupt().
> >
>
> hm. Under what circumstances do you expect this test to trigger?
e.g. by the following:
static inline int get_futex_value_locked(int *dest, int __user *from)
{
int ret;
inc_preempt_count();
ret = __copy_from_user_inatomic(dest, from, sizeof(int));
dec_preempt_count();
preempt_check_resched();
return ret ? -EFAULT : 0;
}
in_interrupt only checks for HARDIRQ_MASK and SOFTIRQ_MASK but not
for the preemption counter. This is not a theory, we had a bug report
concerning a "bad: scheduling while atomic!" warning.
blue skies,
Martin
Martin Schwidefsky
Linux for zSeries Development & Services
IBM Deutschland Entwicklung GmbH
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