On Mon, Mar 18, 2019 at 04:33:22PM +0100, Oleg Nesterov wrote: > On 03/18, Sudeep Holla wrote: > > > > --- a/arch/x86/entry/common.c > > +++ b/arch/x86/entry/common.c > > @@ -70,22 +70,16 @@ static long syscall_trace_enter(struct pt_regs *regs) > > > > struct thread_info *ti = current_thread_info(); > > unsigned long ret = 0; > > - bool emulated = false; > > u32 work; > > > > if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) > > BUG_ON(regs != task_pt_regs(current)); > > > > - work = READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY; > > - > > - if (unlikely(work & _TIF_SYSCALL_EMU)) > > - emulated = true; > > - > > - if ((emulated || (work & _TIF_SYSCALL_TRACE)) && > > - tracehook_report_syscall_entry(regs)) > > + if (unlikely(ptrace_syscall_enter(regs))) > > return -1L; > > > > - if (emulated) > > + work = READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY; > > + if ((work & _TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) > > return -1L; > [...]
> > And it seems that _TIF_WORK_SYSCALL_ENTRY needs some cleanups too... We don't > need > "& _TIF_WORK_SYSCALL_ENTRY" in syscall_trace_enter, and > _TIF_WORK_SYSCALL_ENTRY > should not include _TIF_NOHZ? > I was about to post the updated version and checked this to make sure I have covered everything or not. I had missed the above comment. All architectures have _TIF_NOHZ in their mask that they check to do work. And from x86, I read "...syscall_trace_enter(). Also includes TIF_NOHZ for enter_from_user_mode()" So I don't understand why _TIF_NOHZ needs to be dropped. Also if we need to drop, we can address that separately examining all archs. I will post the cleanup as you suggested for now. -- Regards, Sudeep
