linux-kernel - [PATCH 2/3] rseq: remove redundant access

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Message-Id: <20210413073657.2308450-3-eric.dumazet@gmail.com>
Date:   Tue, 13 Apr 2021 00:36:56 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Ingo Molnar <mingo@...nel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     "Paul E . McKenney" <paulmck@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>,
        Arjun Roy <arjunroy@...gle.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH 2/3] rseq: remove redundant access_ok()

From: Eric Dumazet <edumazet@...gle.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()

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: "Paul E. McKenney" <paulmck@...nel.org>
Cc: Boqun Feng <boqun.feng@...il.com>
Cc: Arjun Roy <arjunroy@...gle.com>
Cc: Ingo Molnar <mingo@...nel.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