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Message-Id: <20090330133531.f5d99c09.akpm@linux-foundation.org>
Date: Mon, 30 Mar 2009 13:35:31 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Roel Kluin <roel.kluin@...il.com>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org
Subject: Re: [PATCH] hvc_console: prevent wrapping in hvc_console_print()
On Tue, 17 Mar 2009 13:19:55 +0100
Roel Kluin <roel.kluin@...il.com> wrote:
> This was found by code analysis, is it needed?
> ------------------------------>8-------------8<---------------------------------
> If we subtract too much on unsigned i it wraps.
>
> Signed-off-by: Roel Kluin <roel.kluin@...il.com>
> ---
> diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
> index 94e7e3c..d06313c 100644
> --- a/drivers/char/hvc_console.c
> +++ b/drivers/char/hvc_console.c
> @@ -161,10 +161,10 @@ static void hvc_console_print(struct console *co, const char *b,
> }
> } else {
> r = cons_ops[index]->put_chars(vtermnos[index], c, i);
> - if (r <= 0) {
> + if (r <= 0 || r > i) {
> /* throw away chars on error */
> i = 0;
> - } else if (r > 0) {
> + } else {
> i -= r;
> if (i > 0)
> memmove(c, c+r, i);
I expect that ->put_chars() will either return a -ve errno or will
return the number of chars which were written, which will be less than
or equal to `i'.
Or maybe I miss your point.
Guys, could we have a MAINTAINERS entry for this driver please?
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