Re: [PATCH 2/6] ptrace: introduce ptrace_syscall_enter to consolidate PTRACE_SYSEMU handling

Sudeep Holla
2019-03-04T12:27:25Z

On Mon, Mar 04, 2019 at 06:23:32AM -0600, Segher Boessenkool wrote:
> On Mon, Mar 04, 2019 at 10:46:43AM +0000, Sudeep Holla wrote:
> > On Mon, Mar 04, 2019 at 08:03:47AM +0000, Haibo Xu (Arm Technology China) wrote:
> > > On 2019/3/1 2:32, Sudeep Holla wrote:
> > > > +long ptrace_syscall_enter(struct pt_regs *regs)
> > > > +{
> > > > +#ifdef TIF_SYSCALL_EMU
> > > > + if (test_thread_flag(TIF_SYSCALL_EMU)) {
> > > > + if (tracehook_report_syscall_entry(regs));
> > >
> > > Shall we remove the semi-colon at end of the above line?
> >
> > Added intentionally to keep GCC happy.
>
> GCC warns because the user explicitly asked for it, with __must_check.
> If you want to do things with an "if" like this, you should write e.g.
>
> if (tracehook_report_syscall_entry(regs))
> /*
> * We can ignore the return code here, because of
> * X and Y and Z.
> */
> ;
>
> Or it probably is nicer to use a block:
>
> if (tracehook_report_syscall_entry(regs)) {
> /*
> * We can ignore the return code here, because of
> * X and Y and Z.
> */
> }
>
> The point is, you *always* should have a nice fat comment if you are
> ignoring the return code of a __must_check function.
>

Agreed, will add the comment.

--
Regards,
Sudeep