From: Ilya Zykov <linux@izyk.ru>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.cz>,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org
Subject: Re: [PATCH 6/7] n_tty: Fix unsafe update of available buffer space
Date: Wed, 20 Mar 2013 00:26:57 +0400 [thread overview]
Message-ID: <5148CA11.3010106@izyk.ru> (raw)
In-Reply-To: <1363703218-32333-3-git-send-email-peter@hurleysoftware.com>
On 19.03.2013 18:26, Peter Hurley wrote:
> receive_room is used to control the amount of data the flip
> buffer work can push to the read buffer. This update is unsafe:
>
> CPU 0 | CPU 1
> |
> | n_tty_read()
> | n_tty_set_room()
> | left = <calc of space>
> n_tty_receive_buf() |
> <push data to buffer> |
> n_tty_set_room() |
> left = <calc of space> |
> tty->receive_room = left |
> | tty->receive_room = left
>
> receive_room is now updated with a stale calculation of the
> available buffer space, and the subsequent work loop will likely
> overwrite unread data in the input buffer.
>
Sounds reasonable to me.
Thank you.
Ilya Zykov <linux@izyk.ru>
next prev parent reply other threads:[~2013-03-19 20:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 13:38 [PATCH 0/7] n_tty fixes Peter Hurley
2013-03-06 13:38 ` [PATCH 1/7] n_tty: Fix unsafe driver-side signals Peter Hurley
2013-03-06 13:38 ` [PATCH 2/7] n_tty: Lock access to tty->pgrp for POSIX job control Peter Hurley
2013-03-06 13:38 ` [PATCH 3/7] tty: Fix checkpatch errors in tty_ldisc.h Peter Hurley
2013-03-06 13:38 ` [PATCH 4/7] n_tty: Encapsulate minimum_to_wake within N_TTY Peter Hurley
2013-03-18 23:15 ` Greg Kroah-Hartman
2013-03-19 13:57 ` Peter Hurley
2013-03-19 14:10 ` Greg Kroah-Hartman
2013-03-19 14:26 ` Peter Hurley
2013-03-19 14:26 ` [PATCH 5/7] n_tty: Untangle read completion variables Peter Hurley
2013-03-19 14:26 ` [PATCH 6/7] n_tty: Fix unsafe update of available buffer space Peter Hurley
2013-03-19 20:26 ` Ilya Zykov [this message]
2013-03-19 14:26 ` [PATCH 7/7] n_tty: Buffer work should not reschedule itself Peter Hurley
2013-03-19 20:27 ` Ilya Zykov
2013-06-15 11:28 ` [PATCH 0/4] [resend] n_tty fixes Peter Hurley
2013-06-15 11:28 ` [PATCH 1/4] n_tty: Encapsulate minimum_to_wake within N_TTY Peter Hurley
2013-06-15 11:28 ` [PATCH 2/4] n_tty: Untangle read completion variables Peter Hurley
2013-06-15 11:28 ` [PATCH 3/4] n_tty: Fix unsafe update of available buffer space Peter Hurley
2013-06-15 11:28 ` [PATCH 4/4] n_tty: Buffer work should not reschedule itself Peter Hurley
2013-06-17 19:58 ` [PATCH 0/4] [resend] n_tty fixes Greg Kroah-Hartman
2013-03-06 13:38 ` [PATCH 5/7] n_tty: Untangle read completion variables Peter Hurley
2013-03-06 13:38 ` [PATCH 6/7] n_tty: Fix unsafe update of available buffer space Peter Hurley
2013-03-06 13:38 ` [PATCH 7/7] n_tty: Buffer work should not reschedule itself Peter Hurley
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