2019-07-04 17:41:43

by Luke Nowakowski-Krijger

Subject: [Linux-kernel-mentee, PATCH] media: dvb_frontend.h: Fix shifting signed 32-bit value problem

Fix DVBFE_ALGO_RECOVERY and DVBFE_ALGO_SEARCH_ERROR to use U cast which
fixes undefined behavior error by certain compilers.

Signed-off-by: Luke Nowakowski-Krijger <[email protected]>
---
include/media/dvb_frontend.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h
index f05cd7b94a2c..472fe5871d94 100644
--- a/include/media/dvb_frontend.h
+++ b/include/media/dvb_frontend.h
@@ -144,7 +144,7 @@ enum dvbfe_algo {
DVBFE_ALGO_HW = (1 << 0),
DVBFE_ALGO_SW = (1 << 1),
DVBFE_ALGO_CUSTOM = (1 << 2),
- DVBFE_ALGO_RECOVERY = (1 << 31)
+ DVBFE_ALGO_RECOVERY = (1U << 31)
};

/**
@@ -175,7 +175,7 @@ enum dvbfe_search {
DVBFE_ALGO_SEARCH_FAILED = (1 << 2),
DVBFE_ALGO_SEARCH_INVALID = (1 << 3),
DVBFE_ALGO_SEARCH_AGAIN = (1 << 4),
- DVBFE_ALGO_SEARCH_ERROR = (1 << 31),
+ DVBFE_ALGO_SEARCH_ERROR = (1U << 31),
};

/**
--
2.20.1

2019-07-04 18:55:07

by Fabio Estevam

Subject: Re: [Linux-kernel-mentee, PATCH] media: dvb_frontend.h: Fix shifting signed 32-bit value problem

Hi Luke,

On Thu, Jul 4, 2019 at 3:22 PM Luke Nowakowski-Krijger
<[email protected]> wrote:
>
> Fix DVBFE_ALGO_RECOVERY and DVBFE_ALGO_SEARCH_ERROR to use U cast which
> fixes undefined behavior error by certain compilers.
>
> Signed-off-by: Luke Nowakowski-Krijger <[email protected]>
> ---
> include/media/dvb_frontend.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h
> index f05cd7b94a2c..472fe5871d94 100644
> --- a/include/media/dvb_frontend.h
> +++ b/include/media/dvb_frontend.h
> @@ -144,7 +144,7 @@ enum dvbfe_algo {
> DVBFE_ALGO_HW = (1 << 0),
> DVBFE_ALGO_SW = (1 << 1),
> DVBFE_ALGO_CUSTOM = (1 << 2),
> - DVBFE_ALGO_RECOVERY = (1 << 31)
> + DVBFE_ALGO_RECOVERY = (1U << 31)

You could switch all these definitions to use the BIT() macro instead.

2019-07-05 06:02:25

by Greg Kroah-Hartman

Subject: Re: [Linux-kernel-mentees] [Linux-kernel-mentee, PATCH] media: dvb_frontend.h: Fix shifting signed 32-bit value problem

On Thu, Jul 04, 2019 at 10:04:22AM -0700, Luke Nowakowski-Krijger wrote:
> Fix DVBFE_ALGO_RECOVERY and DVBFE_ALGO_SEARCH_ERROR to use U cast which
> fixes undefined behavior error by certain compilers.
>
> Signed-off-by: Luke Nowakowski-Krijger <[email protected]>
> ---
> include/media/dvb_frontend.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h
> index f05cd7b94a2c..472fe5871d94 100644
> --- a/include/media/dvb_frontend.h
> +++ b/include/media/dvb_frontend.h
> @@ -144,7 +144,7 @@ enum dvbfe_algo {
> DVBFE_ALGO_HW = (1 << 0),
> DVBFE_ALGO_SW = (1 << 1),
> DVBFE_ALGO_CUSTOM = (1 << 2),
> - DVBFE_ALGO_RECOVERY = (1 << 31)
> + DVBFE_ALGO_RECOVERY = (1U << 31)

BIT() is better for stuff like this.

thanks,

greg k-h