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SubjectRe: [PATCH v2] register console: prevent adding the same console twice
ping?

Am 2013-03-25 09:59, schrieb Andreas Bießmann:
> This patch guards the console_drivers list to be corrupted. The
> for_each_console() macro insist on a strictly forward list ended by
> NULL:
>
> con0->next->con1->next->NULL
>
> Without this patch it may happen easily to destroy this list for
> example by
> adding 'earlyprintk' twice, especially on embedded devices where the
> early
> console is often a single static instance. This will result in the
> following
> list:
>
> con0->next->con0
>
> This in turn will result in an endless loop in console_unlock() later
> on by
> printing the first __log_buf line endlessly.
>
> Signed-off-by: Andreas Bießmann <andreas@biessmann.de>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Kay Sievers <kay@vrfy.org>
> Cc: Ben Hutchings <ben@decadent.org.uk>
> Cc: stable@kernel.org
> ---
> since v1:
> * use WARN() as Ben suggested
> * print 'already registered' instead of 'prevent registering'
>
> kernel/printk.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/kernel/printk.c b/kernel/printk.c
> index abbdd9e..180ee25 100644
> --- a/kernel/printk.c
> +++ b/kernel/printk.c
> @@ -2214,6 +2214,13 @@ void register_console(struct console *newcon)
> unsigned long flags;
> struct console *bcon = NULL;
>
> + if (console_drivers)
> + for_each_console(bcon)
> + if (WARN(bcon == newcon,
> + "console '%s%d' already registered\n",
> + bcon->name, bcon->index))
> + return;
> +
> /*
> * before we register a new CON_BOOT console, make sure we don't
> * already have a valid console
--
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