Use of sti in entry.S question

2.5/arch/i386/kernel/entry.S:

In work_resched, schedule may be called with
interrupts off:

work_resched:
call schedule
cli # make sure we don't miss an interrupt
# setting need_resched or sigpending # between sampling and the iret
movl TI_FLAGS(%ebp), %ecx
andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
# than syscall tracing?
jz restore_all
testb $_TIF_NEED_RESCHED, %cl
jnz work_resched <====== schedule with interrupts disabled

Is this a mistake or an optimization? Elsewhere in entry.S, interrupts are turned on before calling schedule:

Quoted 2 lines

Is this a mistake or an optimization? Elsewhere in entry.S, interrupts are turned on before calling schedule:

It's a mistake, but a harmless one. The scheduler turns off interrupts soon itself and the instructions it executes before that don't care. The only reason it's not recommended to call schedule with interrupts off is that the scheduler will turn them on again, usually breaking your critical section. In this case it's ok because the next instrution is a cli again.