On 2019-06-26 15:35:04 [+0800], xiaoqiang.zhao wrote: > Hi, guys: Hi, > I have built a kernel 4.4.38-rt49 with CONFIG_PREEMPT_RT_FULL=y , the > kernel crash when I run the UnixBench of spawn test case. Can you forward to something newer, 4.4.179-rt181 for instance? > Here is the oops info: … > The call path is: > > do_fork-> copy_process -> threadgroup_change_end -> percpu_up_read(call > preempt_disable) -> __percpu_up_read > > -> wake_up -> rt_spin_lock -> rt_spin_lock_slowlock -> schedule(call > preempt_disable again) -> __schedule > > -> schedule_debug -> in_aotmic_preempt_off (return true, preempt_count == > 2) -> __schedule_bug ( leads to kernel pagefault exception, OOPS!!) > > Before schedule, we have call preempt_disable twice, this will definitely > bump preempt_count to 2 and something probably disabled preemption before that. > in_atomic_preempt_off will fail. > > I did not figure out: WHY we call schedule inside rt_spin_lock_slowlock > and under what condition this call is correct ? if the lock is acquired you schedule out and wait und it is available again. Sebastian
