From: David Laight <David.Laight@ACULAB.COM>
To: 'Al Viro' <viro@zeniv.linux.org.uk>
Cc: "'Michael S. Tsirkin'" <mst@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jason Wang <jasowang@redhat.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
Netdev <netdev@vger.kernel.org>
Subject: RE: [PATCH RFC] uaccess: user_access_begin_after_access_ok()
Date: Wed, 3 Jun 2020 08:08:17 +0000 [thread overview]
Message-ID: <a6d865f0dc7a427bb180cf451b8d470f@AcuMS.aculab.com> (raw)
In-Reply-To: <20200602215827.GP23230@ZenIV.linux.org.uk>
From: Al Viro <viro@ftp.linux.org.uk> On Behalf Of Al Viro
> Sent: 02 June 2020 22:58
> On Tue, Jun 02, 2020 at 08:41:38PM +0000, David Laight wrote:
>
> > In which case you need a 'user_access_begin' that takes the mm
> > as an additional parameter.
>
> What does any of that have to do with mm? Details, please.
Actually probably nothing.
I was sort of thinking that maybe the user process's memory
map (mm?) would be temporarily 'attached' to the kernel thread
so that it used the normal copy_to/from_user() fault
handling to access the 'other' process.
In which case you'd want to do the bound check against the
limit of the user addresses in the mm rather than those of
the current process.
But later posts probably imply that it is all done differently.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-06-03 8:08 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-02 8:45 Michael S. Tsirkin
2020-06-02 10:15 ` Jason Wang
2020-06-02 16:33 ` Al Viro
2020-06-02 17:18 ` Linus Torvalds
2020-06-02 17:44 ` Al Viro
2020-06-02 17:46 ` Al Viro
2020-06-02 20:32 ` Michael S. Tsirkin
2020-06-02 20:41 ` David Laight
2020-06-02 21:58 ` Al Viro
2020-06-03 8:08 ` David Laight [this message]
2020-06-02 20:43 ` Linus Torvalds
2020-06-03 6:01 ` Michael S. Tsirkin
[not found] ` <CAHk-=wi3=QuD30fRq8fYYTj9WmkgeZ0VR_Sh3DQHU+nmwj-jMg@mail.gmail.com>
2020-06-03 16:59 ` Linus Torvalds
2020-06-02 16:30 ` Al Viro
2020-06-02 20:42 ` Michael S. Tsirkin
2020-06-02 22:10 ` Al Viro
2020-06-03 5:17 ` Michael S. Tsirkin
2020-06-03 1:48 ` Al Viro
2020-06-03 3:57 ` Jason Wang
2020-06-03 4:18 ` Al Viro
2020-06-03 5:18 ` Jason Wang
2020-06-03 5:46 ` Michael S. Tsirkin
2020-06-03 6:23 ` Jason Wang
2020-06-03 6:30 ` Michael S. Tsirkin
2020-06-03 6:36 ` Jason Wang
2020-06-04 16:49 ` Michael S. Tsirkin
2020-06-05 10:03 ` Jason Wang
2020-06-06 20:08 ` Michael S. Tsirkin
2020-06-03 6:25 ` Michael S. Tsirkin
2020-06-03 5:29 ` Michael S. Tsirkin
2020-06-03 16:52 ` Al Viro
2020-06-04 6:10 ` Jason Wang
2020-06-04 14:59 ` Al Viro
2020-06-04 16:46 ` Michael S. Tsirkin
2020-06-04 10:10 ` Michael S. Tsirkin
2020-06-04 15:03 ` Al Viro
2020-06-04 16:47 ` Michael S. Tsirkin
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