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From:   Ze Gao <zegao2021@gmail.com>
Date:   Tue, 16 May 2023 17:35:50 +0800
Message-ID: <CAD8CoPCen5Vx33Q1hYJ4T7Q9xhZa63OA52B606omkBttRWpkFg@mail.gmail.com>
Subject: Re: [PATCH v2 2/4] fprobe: make fprobe_kprobe_handler recursion free
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vasily Gorbik <gor@linux.ibm.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
        bpf@vger.kernel.org, Conor Dooley <conor@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>, Yonghong Song <yhs@fb.com>,
        Ze Gao <zegao@tencent.com>
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Thanks for pointing this out,  I'll get it all fixed ASAP.

Regards,
Ze

On Tue, May 16, 2023 at 5:16=E2=80=AFPM Peter Zijlstra <peterz@infradead.or=
g> wrote:
>
> On Tue, May 16, 2023 at 03:18:28PM +0800, Ze Gao wrote:
>
> > +static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
> > +             struct ftrace_ops *ops, struct ftrace_regs *fregs)
> > +{
> > +     struct fprobe *fp;
> > +     int bit;
> > +
> > +     fp =3D container_of(ops, struct fprobe, ops);
> > +     if (fprobe_disabled(fp))
> > +             return;
> > +
> > +     /* recursion detection has to go before any traceable function an=
d
> > +      * all functions before this point should be marked as notrace
> > +      */
> > +     bit =3D ftrace_test_recursion_trylock(ip, parent_ip);
> > +     if (bit < 0) {
> > +             fp->nmissed++;
> > +             return;
> > +     }
> > +     __fprobe_handler(ip, parent_ip, ops, fregs);
> >       ftrace_test_recursion_unlock(bit);
> > +
> >  }
> >  NOKPROBE_SYMBOL(fprobe_handler);
> >
> >  static void fprobe_kprobe_handler(unsigned long ip, unsigned long pare=
nt_ip,
> >                                 struct ftrace_ops *ops, struct ftrace_r=
egs *fregs)
> >  {
> > -     struct fprobe *fp =3D container_of(ops, struct fprobe, ops);
> > +     struct fprobe *fp;
> > +     int bit;
> > +
> > +     fp =3D container_of(ops, struct fprobe, ops);
> > +     if (fprobe_disabled(fp))
> > +             return;
> > +
> > +     /* recursion detection has to go before any traceable function an=
d
> > +      * all functions called before this point should be marked as not=
race
> > +      */
> > +     bit =3D ftrace_test_recursion_trylock(ip, parent_ip);
> > +     if (bit < 0) {
> > +             fp->nmissed++;
> > +             return;
> > +     }
>
> Please don't use this comment style; multi line comments go like:
>
>         /*
>          * Multi line comment ...
>          *                    ... is symmetric.
>          */
>
> Same for your next patch.