From: Jamie Lokier <jamie@shareable.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>,
Vitaly Mayatskikh <v.mayatskih@gmail.com>,
Josef Bacik <josef@redhat.com>,
sandeen@redhat.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] Perform check in iov_iter_fault_in_readable() by check_readable_bytes()
Date: Mon, 18 May 2009 10:48:08 +0100 [thread overview]
Message-ID: <20090518094808.GA12041@shareable.org> (raw)
In-Reply-To: <20090518093136.152a1bb7@lxorguk.ukuu.org.uk>
Alan Cox wrote:
> > System calls don't trigger SIGSEGVs so they can't rely on that when
> > calling read(). I'm not sure how they handle that.
>
> Usually by touching the pages before the syscall.
Makes sense.
> (You can't rely on -EFAULT either in POSIX, its optional that it
> bothers to tell you and for example on MMUless it may well not)
On MMUless you wouldn't use page protection as a GC technique :-)
Is EFAULT really optional on systems with page protection?
-- Jamie
next prev parent reply other threads:[~2009-05-18 9:48 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-14 16:18 [PATCH 0/2] sys_write() should write all valid data Vitaly Mayatskikh
2009-05-14 16:19 ` [PATCH 1/2] Introduce check_readable_bytes() Vitaly Mayatskikh
2009-05-14 17:40 ` Josef Bacik
2009-05-14 17:57 ` Vitaly Mayatskikh
2009-05-14 16:19 ` [PATCH 2/2] Perform check in iov_iter_fault_in_readable() by check_readable_bytes() Vitaly Mayatskikh
2009-05-15 6:56 ` Andi Kleen
2009-05-15 7:56 ` Vitaly Mayatskikh
2009-05-15 9:38 ` Andi Kleen
2009-05-15 11:56 ` Vitaly Mayatskikh
2009-05-15 12:19 ` Andi Kleen
2009-05-15 13:43 ` Jamie Lokier
2009-05-15 14:01 ` Andi Kleen
2009-05-15 14:37 ` Jamie Lokier
2009-05-18 8:31 ` Alan Cox
2009-05-18 9:48 ` Jamie Lokier [this message]
2009-05-18 10:03 ` Alan Cox
2009-05-18 10:16 ` Andi Kleen
2009-05-19 8:55 ` Pavel Machek
2009-05-14 18:02 ` [PATCH 0/2] sys_write() should write all valid data Josef Bacik
2009-05-14 18:48 ` Vitaly Mayatskikh
2009-05-14 19:05 ` Josef Bacik
2009-05-15 6:52 ` Andi Kleen
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