From: Oleg Nesterov <oleg@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-kernel@vger.kernel.org, io-uring@vger.kernel.org,
peterz@infradead.org, tglx@linutronix.de
Subject: Re: [PATCH 4/6] kernel: add support for TIF_NOTIFY_SIGNAL
Date: Thu, 8 Oct 2020 15:53:26 +0200 [thread overview]
Message-ID: <20201008135325.GG9995@redhat.com> (raw)
In-Reply-To: <20201005150438.6628-5-axboe@kernel.dk>
On 10/05, Jens Axboe wrote:
>
> static inline int signal_pending(struct task_struct *p)
> {
> +#ifdef TIF_NOTIFY_SIGNAL
> + /*
> + * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
> + * behavior in terms of ensuring that we break out of wait loops
> + * so that notify signal callbacks can be processed.
> + */
> + if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
> + return 1;
> +#endif
> return task_sigpending(p);
> }
perhaps we can add test_tsk_thread_mask() later...
> static inline void restore_saved_sigmask_unless(bool interrupted)
> {
> - if (interrupted)
> + if (interrupted) {
> +#ifdef TIF_NOTIFY_SIGNAL
> + WARN_ON(!test_thread_flag(TIF_SIGPENDING) &&
> + !test_thread_flag(TIF_NOTIFY_SIGNAL));
> +#else
> WARN_ON(!test_thread_flag(TIF_SIGPENDING));
> - else
> +#endif
> + } else {
> restore_saved_sigmask();
> + }
I'd suggest to simply do
- WARN_ON(!test_thread_flag(TIF_SIGPENDING));
+ WARN_ON(!signal_pending(current);
> --- a/kernel/entry/kvm.c
> +++ b/kernel/entry/kvm.c
> @@ -8,6 +8,9 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work)
> do {
> int ret;
>
> + if (ti_work & _TIF_NOTIFY_SIGNAL)
> + tracehook_notify_signal();
Can't really comment this change, but to me it would be more safe to
simply return -EINTR.
Or perhaps even better, treat _TIF_NOTIFY_SIGNAL and _TIF_SIGPENDING
equally:
- if (ti_work & _TIF_SIGPENDING) {
+ if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
kvm_handle_signal_exit(vcpu);
return -EINTR;
Oleg.
next prev parent reply other threads:[~2020-10-08 13:53 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 15:04 [PATCHSET RFC v3 0/6] Add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-05 15:04 ` [PATCH 1/6] tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume() Jens Axboe
2020-10-08 12:37 ` Oleg Nesterov
2020-10-08 13:36 ` Jens Axboe
2020-10-05 15:04 ` [PATCH 2/6] kernel: add task_sigpending() helper Jens Axboe
2020-10-08 12:58 ` Oleg Nesterov
2020-10-08 13:36 ` Jens Axboe
2020-10-08 13:24 ` Oleg Nesterov
2020-10-08 13:38 ` Jens Axboe
2020-10-05 15:04 ` [PATCH 3/6] kernel: split syscall restart from signal handling Jens Axboe
2020-10-08 14:21 ` Oleg Nesterov
2020-10-08 14:31 ` Jens Axboe
2020-10-08 14:41 ` Jens Axboe
2020-10-08 14:45 ` Oleg Nesterov
2020-10-08 14:47 ` Jens Axboe
2020-10-05 15:04 ` [PATCH 4/6] kernel: add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-08 13:53 ` Oleg Nesterov [this message]
2020-10-08 14:07 ` Jens Axboe
2020-10-08 14:27 ` Oleg Nesterov
2020-10-05 15:04 ` [PATCH 5/6] x86: define _TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-05 15:04 ` [PATCH 6/6] task_work: use TIF_NOTIFY_SIGNAL if available Jens Axboe
2020-10-08 14:56 ` [PATCHSET RFC v3 0/6] Add support for TIF_NOTIFY_SIGNAL Oleg Nesterov
2020-10-08 15:00 ` Jens Axboe
2020-10-09 8:01 ` Miroslav Benes
2020-10-09 15:21 ` Jens Axboe
2020-10-10 16:53 ` Jens Axboe
2020-10-12 17:27 ` Miroslav Benes
2020-10-13 19:39 ` Jens Axboe
2020-10-13 23:34 ` Thomas Gleixner
2020-10-13 23:37 ` Jens Axboe
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