linux-kernel - Re: [PATCH 4/5] x86: wire up TIF_NOTIFY

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Message-ID: <f432092d-5304-110e-a03f-e97c7993a68b@kernel.dk>
Date:   Thu, 15 Oct 2020 08:42:08 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Oleg Nesterov <oleg@...hat.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org,
        io-uring@...r.kernel.org, peterz@...radead.org
Subject: Re: [PATCH 4/5] x86: wire up TIF_NOTIFY_SIGNAL

On 10/15/20 8:36 AM, Oleg Nesterov wrote:
> On 10/15, Jens Axboe wrote:
>>
>> static void handle_signal_work(ti_work, regs)
>> {
>> 	if (ti_work & _TIF_NOTIFY_SIGNAL)
>>         	tracehook_notify_signal();
>>
>> 	if (ti_work & _TIF_SIGPENDING)
>>         	arch_do_signal(regs);
>> }
>>
>> and then we can skip modifying arch_do_signal() all together, as it'll
>> only be called if _TIF_SIGPENDING is set.
> 
> No, this can't work. We need to restart the syscall if TIF_NOTIFY_SIGNAL.

Yeah braino, Thomas caught that one too.

-- 
Jens Axboe