From: Catalin Marinas <catalin.marinas@arm.com>
To: Tomko <tomko@haha.com>
Cc: Jan-Benedict Glaw <jbglaw@lug-owl.de>, linux-kernel@vger.kernel.org
Subject: Re: Why system call need to copy the date from the userspace before using it
Date: Wed, 13 Apr 2005 12:10:46 +0100 [thread overview]
Message-ID: <tnxd5szvsnd.fsf@arm.com> (raw)
In-Reply-To: <425CF7DB.4000407@haha.com> (tomko@haha.com's message of "Wed, 13 Apr 2005 18:43:39 +0800")
Tomko <tomko@haha.com> wrote:
> Inside the system call , the kernel often copy the data by calling
> copy_from_user() rather than just using strcpy(), is it because the
> memory mapping in kenel space is different from user space?
No, it is because this function checks whether the access to the user
space address is OK. There are situations when it can also sleep (page
not present).
--
Catalin
next prev parent reply other threads:[~2005-04-13 11:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-13 4:21 Why system call need to copy the date from the userspace before using it Tomko
2005-04-13 5:30 ` Vadim Lobanov
2005-04-13 10:29 ` Jan-Benedict Glaw
2005-04-13 10:43 ` Tomko
2005-04-13 11:10 ` Catalin Marinas [this message]
2005-04-14 2:10 ` Tomko
2005-04-14 2:18 ` David Schwartz
2005-04-14 14:05 ` Helge Hafting
2005-04-13 11:33 ` Benjamin Herrenschmidt
2005-04-13 11:59 ` Hacksaw
2005-04-13 12:40 ` Richard B. Johnson
2005-04-13 18:37 ` Theodore Ts'o
2005-04-13 19:20 ` Richard B. Johnson
2005-04-16 4:50 ` Hacksaw
2005-04-16 5:18 ` Vadim Lobanov
2005-04-16 8:30 ` Hacksaw
2005-04-16 19:35 ` Vadim Lobanov
2005-04-16 23:46 ` David Wagner
-- strict thread matches above, loose matches on Subject: below --
2005-04-13 6:48 Vadim Lobanov
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