[lustre-devel] [PATCH] staging: kernel.h: Prevent macro expantion bug in container_of_safe()

[NeilBrown <neilb@suse.com>]

On Thu, Apr 26 2018, Dan Carpenter wrote:

> There aren't many users of this so it doesn't cause a problem, but we
> obviously want to use "__mptr" here instead of "ptr" to prevent the
> parameter from being executed twice.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index b5a8e78c6c75..593fb8d250a2 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -978,7 +978,7 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
>  	BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&	\
>  			 !__same_type(*(ptr), void),			\
>  			 "pointer type mismatch in container_of()");	\
> -	IS_ERR_OR_NULL(ptr) ? ERR_CAST(ptr) :				\
> +	IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) :			\
>  		((type *)(__mptr - offsetof(type, member))); })
>  
>  /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */

Arg, of course.  Thanks.
Acked-by: NeilBrown <neilb@suse.com>

Thanks,
NeilBrown
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