linux-kernel - Re: [PATCH 3/6] x86: clean up _TIF_SYSCALL_EMU handling using ptrace_syscall

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Message-ID: <20190304101205.GA1504@e107155-lin>
Date:   Mon, 4 Mar 2019 10:12:05 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     "Haibo Xu (Arm Technology China)" <Haibo.Xu@....com>
Cc:     "x86@...nel.org" <x86@...nel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        Catalin Marinas <Catalin.Marinas@....com>,
        Will Deacon <Will.Deacon@....com>,
        Oleg Nesterov <oleg@...hat.com>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Richard Weinberger <richard@....at>,
        "jdike@...toit.com" <jdike@...toit.com>,
        Steve Capper <Steve.Capper@....com>,
        "Bin Lu (Arm Technology China)" <Bin.Lu@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH 3/6] x86: clean up _TIF_SYSCALL_EMU handling using
 ptrace_syscall_enter hook

On Mon, Mar 04, 2019 at 08:25:28AM +0000, Haibo Xu (Arm Technology China) wrote:
> On 2019/3/1 2:32, Sudeep Holla wrote:
> > Now that we have a new hook ptrace_syscall_enter that can be called from
> > syscall entry code and it handles PTRACE_SYSEMU in generic code, we
> > can do some cleanup using the same in syscall_trace_enter.
> > 
> > Further the extra logic to find single stepping PTRACE_SYSEMU_SINGLESTEP
> > in syscall_slow_exit_work seems unnecessary. Let's remove the same.
> 
> I think we should not change the logic here. Is so, it will double the report of syscall
> when PTRACE_SYSEMU_SINGLESTEP is enabled.
>

I don't think that should happen, but I may be missing something.
Can you explain how ?

--
Regards,
Sudeep