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Message-ID: <4CA4C0FF.90304@mail.berlios.de>
Date: Thu, 30 Sep 2010 18:55:27 +0200
From: Stefan Weil <weil@mail.berlios.de>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] [PATCH] console: Avoid dereferencing NULL
	active_console
References: <1284988279-8900-1-git-send-email-stefanha@linux.vnet.ibm.com>
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To: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, qemu-devel@nongnu.org, Michal Suchanek <hramrach@centrum.cz>, Gerd Hoffmann <kraxel@redhat.com>

Am 20.09.2010 15:11, schrieb Stefan Hajnoczi:
> The console_select() function does not check that active_console is
> non-NULL before dereferencing it. When invoked with qemu -nodefaults it
> is possible to hit this case.
>
> This patch checks that active_console is non-NULL before stashing away
> the old console dimensions in console_select().
>
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
> console.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/console.c b/console.c
> index 698bc10..c1728b1 100644
> --- a/console.c
> +++ b/console.c
> @@ -1060,8 +1060,10 @@ void console_select(unsigned int index)
>
> if (index >= MAX_CONSOLES)
> return;
> - active_console->g_width = ds_get_width(active_console->ds);
> - active_console->g_height = ds_get_height(active_console->ds);
> + if (active_console) {
> + active_console->g_width = ds_get_width(active_console->ds);
> + active_console->g_height = ds_get_height(active_console->ds);
> + }
> s = consoles[index];
> if (s) {
> DisplayState *ds = s->ds;


To avoid that still more people fix the same bug,
I'd appreciate shorter commit times for simple patches like this one.

Cheers,
Stefan

Acked-by: Stefan Weil <weil@mail.berlios.de>