From: Al Viro <viro@zeniv.linux.org.uk>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
bp@alien8.de
Subject: Re: [PATCH v2] x86: bring back rep movsq for user access on CPUs without ERMS
Date: Mon, 4 Sep 2023 00:28:02 +0100 [thread overview]
Message-ID: <20230903232802.GO3390869@ZenIV> (raw)
In-Reply-To: <CAGudoHHOEMvz6=JZ2XZYKgKTqQ-FeCcXxVEvS2xBncn-ck5JXg@mail.gmail.com>
On Sun, Sep 03, 2023 at 11:18:44PM +0200, Mateusz Guzik wrote:
> On 9/3/23, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > On Sun, 3 Sept 2023 at 14:06, Mateusz Guzik <mjguzik@gmail.com> wrote:
> >>
> >> I don't think it is *that* bad. I did a quick sanity check on that
> >> front by rolling with bpftrace on cases which pass AT_EMPTY_PATH *and*
> >> provide a path.
> >
> > I guess you are right - nobody sane would use AT_EMPTY_PATH except if
> > they don't have a path.
> >
> > Of course, the only reason we're discussing this in the first place is
> > because people are doing insane things, which makes _that_ particular
> > argument very weak indeed...
> >
>
> I put blame on whoever allowed non-NULL path and AT_EMPTY_PATH as a
> valid combination, forcing the user buf to be accessed no matter what.
> But I'm not going to go digging for names. ;)
ITYM s/allowed/mandated/ - AT_EMPTY_PATH with NULL is -EFAULT.
next prev parent reply other threads:[~2023-09-03 23:28 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 14:03 [PATCH v2] x86: bring back rep movsq for user access on CPUs without ERMS Mateusz Guzik
2023-08-30 16:50 ` Linus Torvalds
2023-08-30 20:00 ` Linus Torvalds
2023-09-01 15:20 ` Mateusz Guzik
2023-09-01 15:29 ` Linus Torvalds
2023-09-03 18:49 ` Linus Torvalds
2023-09-03 19:14 ` Linus Torvalds
2023-09-03 20:08 ` Linus Torvalds
2023-09-03 20:48 ` Mateusz Guzik
2023-09-03 20:57 ` Linus Torvalds
2023-09-03 21:06 ` Mateusz Guzik
2023-09-03 21:08 ` Linus Torvalds
2023-09-03 21:18 ` Mateusz Guzik
2023-09-03 23:28 ` Al Viro [this message]
2023-09-03 20:58 ` Mateusz Guzik
2023-09-03 21:05 ` Linus Torvalds
2023-09-03 21:48 ` Ingo Molnar
2023-09-03 22:34 ` Linus Torvalds
2023-09-03 23:15 ` Mateusz Guzik
2023-09-04 3:07 ` Linus Torvalds
2023-09-04 3:17 ` Linus Torvalds
2023-09-04 6:03 ` Mateusz Guzik
2023-09-04 17:28 ` Linus Torvalds
2023-09-05 20:41 ` Mateusz Guzik
2023-09-06 0:16 ` Linus Torvalds
2023-09-06 4:11 ` Mateusz Guzik
2023-09-01 13:33 ` David Laight
2023-09-01 15:28 ` Mateusz Guzik
2023-09-03 20:42 ` David Laight
2023-09-10 10:53 ` Mateusz Guzik
2023-09-11 10:37 ` David Laight
2023-09-12 18:48 ` Linus Torvalds
2023-09-12 19:41 ` David Laight
2023-09-12 20:48 ` Linus Torvalds
2023-09-13 8:25 ` David Laight
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