On Tue, 18 Jun 2019, Puranjay Mohan wrote:
> Fix CRAMFS_BLK_FLAG_UNCOMPRESSED to use "U" cast to avoid shifting signed
> 32-bit value by 31 bits problem. This isn't a problem for kernel builds
> with gcc.
>
> This could be problem since this header is part of public API which
> could be included for builds using compilers that don't handle this
> condition safely resulting in undefined behavior.
>
> Signed-off-by: Puranjay Mohan <puranja...@gmail.com>
> Reviewed-by: Christoph Hellwig <h...@lst.de>
> Reviewed-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
> Reviewed-by: Shuah Khan <sk...@linuxfoundation.org>
Acked-by: Nicolas Pitre <n...@fluxnic.net>
> ---
> V2 - use the unsigned constants for all flags, not just one
> RESEND - Added Nicolas Pitre to CC list, added reviewed by tags.
>
> include/uapi/linux/cramfs_fs.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/cramfs_fs.h b/include/uapi/linux/cramfs_fs.h
> index 6713669aa2ed..71cb602d4198 100644
> --- a/include/uapi/linux/cramfs_fs.h
> +++ b/include/uapi/linux/cramfs_fs.h
> @@ -98,8 +98,8 @@ struct cramfs_super {
> *
> * That leaves room for 3 flag bits in the block pointer table.
> */
> -#define CRAMFS_BLK_FLAG_UNCOMPRESSED (1 << 31)
> -#define CRAMFS_BLK_FLAG_DIRECT_PTR (1 << 30)
> +#define CRAMFS_BLK_FLAG_UNCOMPRESSED (1U << 31)
> +#define CRAMFS_BLK_FLAG_DIRECT_PTR (1U << 30)
>
> #define CRAMFS_BLK_FLAGS ( CRAMFS_BLK_FLAG_UNCOMPRESSED \
> | CRAMFS_BLK_FLAG_DIRECT_PTR )
> --
> 2.21.0
>
>
