From: Ravi <kravi26@yahoo.com>
To: Amol Kumar Lad <amolk@ishoni.com>, linux-mm@kvack.org
Subject: Re: copy_from_user
Date: Sun, 22 Dec 2002 17:21:06 -0800 (PST) [thread overview]
Message-ID: <20021223012106.10392.qmail@web12301.mail.yahoo.com> (raw)
In-Reply-To: <1040513191.2250.79.camel@amol.in.ishoni.com>
--- Amol Kumar Lad <amolk@ishoni.com> wrote:
> Suppose kernel tries to do copy_from_user from a pointer
> that does not have any mapping. i.e. not in any VMA (and not
in
> stack area too..).
> Now (for 1386)
> access_ok --> __range_ok
> Suppose the 'from' ptr is within range then how kernel is
> making sure that 'from' is invalid ??
> The page fault handler will see that 'from' has no mapping and
> it will die..
I believe this is handled using the 'fixup' code in
__copy_user_zeroing().
I don't understand the code well though, but I do know that it
works :)
-Ravi.
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next prev parent reply other threads:[~2002-12-23 1:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-21 23:26 copy_from_user Amol Kumar Lad
2002-12-23 1:21 ` Ravi [this message]
2002-12-23 15:02 ` copy_from_user Amol Kumar Lad
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