Re: [v2] ErrHandling:Make IS_ERR_VALUE_U32 as generic API to avoid IS_ERR_VALUE abuses.

From: Kalle Valo
Date: Sat Sep 03 2016 - 10:42:08 EST


Arvind Yadav <arvind.yadav.cs@xxxxxxxxx> wrote:
> IS_ERR_VALUE() assumes that its parameter is an unsigned long.
> It can not be used to check if an 'unsigned int' reflects an error.
> As they pass an 'unsigned int' into a function that takes an
> 'unsigned long' argument. This happens to work because the type
> is sign-extended on 64-bit architectures before it gets converted
> into an unsigned type.
>
> However, anything that passes an 'unsigned short' or 'unsigned int'
> argument into IS_ERR_VALUE() is guaranteed to be broken, as are
> 8-bit integers and types that are wider than 'unsigned long'.
>
> It would be nice to any users that are not passing 'unsigned int'
> arguments.
>
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>

This touches include/linux/err.h and I'm not very enthusiastic to change
anything in include directory without wider support. I recommend first to just
fix bcma. And separately you can try to improve linux/err.h via some more
approariate tree, not via wireless trees.

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https://patchwork.kernel.org/patch/9222139/