Re: [PATCH v2] bug: fix problem including <linux/bug.h> from linux/kernel.h

[Ian Abbott]

On 2017-05-24 17:06, Ian Abbott wrote:
> If "include/linux/kernel.h" includes <linux/bug.h>, a circular
> dependency is introduced when "include/asm-generic/bug.h" includes
> <linux/kernel.h>.  This results in build breakage when something
> includes <asm/bug.h> before <linux/kernel.h> for architectures that
> select `CONFIG_GENERIC_BUG` because `struct bug_entry` is not fully
> declared (not declared at all in fact) before its members are accessed
> by `is_warning_bug()`.
>
> To avoid this problem, remove the inclusion of <linux/kernel.h> from
> "include/asm-generic/bug.h", but include <linux/types.h> from
> "include/linux/bug.h" because it needs the `bool` type.
>
> A consequence of this change is that since most bug-related,
> function-link macros (`BUG()`, `WARN()` etc.) make use of facilities
> provided by <linux/kernel.h>, something else needs to include that
> before those macros are called.
>
> Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> ---
> v2: Fix typo in patch subject line.
> ---
>  include/asm-generic/bug.h | 1 -
>  include/linux/bug.h       | 1 +
>  2 files changed, 1 insertion(+), 1 deletion(-)

This patch and its previous version can be dropped now, since the patch 
that caused the breakage that this patch fixes up 
(<https://lkml.org/lkml/2017/5/23/641>) has been dropped (for now). 
I'll avoid the breakage in the way suggested by Rasmus in 
<https://lkml.org/lkml/2017/5/24/553>.

--
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@xxxxxxxxx> )=-
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