[PATCH 4/5] kernel/debug/kdb/kdb_bp.c: drop negativity check on unsigned value

[PATCH 4/5] kernel/debug/kdb/kdb_bp.c: drop negativity check on unsigned value

[Andrey Utkin]

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=80591
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Andrey Utkin <andrey.krieger.utkin@gmail.com>
---
 kernel/debug/kdb/kdb_bp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c
index 70a5046..f27dfb8 100644
--- a/kernel/debug/kdb/kdb_bp.c
+++ b/kernel/debug/kdb/kdb_bp.c
@@ -39,7 +39,7 @@ static char *kdb_rwtypes[] = {
 
 static char *kdb_bptype(kdb_bp_t *bp)
 {
-	if (bp->bp_type < 0 || bp->bp_type > 4)
+	if (bp->bp_type > 4)
 		return "";
 
 	return kdb_rwtypes[bp->bp_type];
-- 
1.8.5.5

Re: [PATCH 4/5] kernel/debug/kdb/kdb_bp.c: drop negativity check on unsigned value

[walter harms]

Am 18.07.2014 17:34, schrieb Andrey Utkin:
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=80591
> Reported-by: David Binderman <dcb314@hotmail.com>
> Signed-off-by: Andrey Utkin <andrey.krieger.utkin@gmail.com>
> ---
>  kernel/debug/kdb/kdb_bp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c
> index 70a5046..f27dfb8 100644
> --- a/kernel/debug/kdb/kdb_bp.c
> +++ b/kernel/debug/kdb/kdb_bp.c
> @@ -39,7 +39,7 @@ static char *kdb_rwtypes[] = {
>  
>  static char *kdb_bptype(kdb_bp_t *bp)
>  {
> -	if (bp->bp_type < 0 || bp->bp_type > 4)
> +	if (bp->bp_type > 4)
>  		return "";
>  
>  	return kdb_rwtypes[bp->bp_type];

i would expect a ckeck for the upper limit with ARRAY_SIZE(bp->bp_type) here.

re,
 wh

Re: [PATCH 4/5] kernel/debug/kdb/kdb_bp.c: drop negativity check on unsigned value

[Andrey Utkin]

2014-07-18 20:18 GMT+03:00 walter harms <wharms@bfs.de>:
> i would expect a ckeck for the upper limit with ARRAY_SIZE

Thanks, resubmitted.

-- 
Andrey Utkin

Re: [PATCH 4/5] kernel/debug/kdb/kdb_bp.c: drop negativity check on unsigned value

[Dan Carpenter]

On Fri, Jul 18, 2014 at 06:34:52PM +0300, Andrey Utkin wrote:
>  static char *kdb_bptype(kdb_bp_t *bp)
>  {
> -	if (bp->bp_type < 0 || bp->bp_type > 4)
> +	if (bp->bp_type > 4)
>  		return "";

With Smatch, I ignore negative checks in this format.  It's obvious what
the intent is and they are harmless.  Patching them requires a little
review to make sure that someone isn't introducing a bug and can't be
done directly in the email client.

On the other hand, in Smatch I do complain about checks like:

	if (bp->bp_type > 4 || bp->bp_type < 0)

Because only backwards thinking people write checks like that.

regards,
dan carpenter