From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
paulmck <paulmck@kernel.org>, Boqun Feng <boqun.feng@gmail.com>,
Arjun Roy <arjunroy@google.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH 2/3] rseq: remove redundant access_ok()
Date: Tue, 13 Apr 2021 10:34:21 -0400 (EDT) [thread overview]
Message-ID: <1578770214.71411.1618324461988.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20210413073657.2308450-3-eric.dumazet@gmail.com>
----- On Apr 13, 2021, at 3:36 AM, Eric Dumazet eric.dumazet@gmail.com wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> After commit 8f2817701492 ("rseq: Use get_user/put_user rather
> than __get_user/__put_user") we no longer need
> an access_ok() call from __rseq_handle_notify_resume()
While we are doing that, should we also remove the access_ok() check in
rseq_syscall() ? It look like it can also be removed for the exact same
reason outlined here.
Thanks,
Mathieu
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: "Paul E. McKenney" <paulmck@kernel.org>
> Cc: Boqun Feng <boqun.feng@gmail.com>
> Cc: Arjun Roy <arjunroy@google.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> ---
> kernel/rseq.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/kernel/rseq.c b/kernel/rseq.c
> index
> d2689ccbb132c0fc8ec0924008771e5ee1ca855e..57344f9abb43905c7dd2b6081205ff508d963e1e
> 100644
> --- a/kernel/rseq.c
> +++ b/kernel/rseq.c
> @@ -273,8 +273,6 @@ void __rseq_handle_notify_resume(struct ksignal *ksig,
> struct pt_regs *regs)
>
> if (unlikely(t->flags & PF_EXITING))
> return;
> - if (unlikely(!access_ok(t->rseq, sizeof(*t->rseq))))
> - goto error;
> ret = rseq_ip_fixup(regs);
> if (unlikely(ret < 0))
> goto error;
> --
> 2.31.1.295.g9ea45b61b8-goog
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2021-04-13 14:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 7:36 [PATCH 0/3] rseq: minor optimizations Eric Dumazet
2021-04-13 7:36 ` [PATCH 1/3] rseq: optimize rseq_update_cpu_id() Eric Dumazet
2021-04-13 14:29 ` Mathieu Desnoyers
2021-04-13 15:24 ` Eric Dumazet
2021-04-13 7:36 ` [PATCH 2/3] rseq: remove redundant access_ok() Eric Dumazet
2021-04-13 14:34 ` Mathieu Desnoyers [this message]
2021-04-13 15:19 ` Eric Dumazet
2021-04-13 7:36 ` [PATCH 3/3] rseq: optimise for 64bit arches Eric Dumazet
2021-04-13 9:10 ` Peter Zijlstra
2021-04-13 10:36 ` David Laight
2021-04-13 14:21 ` Mathieu Desnoyers
2021-04-13 15:06 ` David Laight
2021-04-13 15:08 ` Mathieu Desnoyers
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