Re: [PATCH] ia64: don't do IA64_CMPXCHG_DEBUG without CONFIG_PRINTK

[Chris Down]

Hi Randy,

Randy Dunlap writes:
> When CONFIG_PRINTK is not set, the CMPXCHG_BUGCHECK() macro calls
> _printk(), but _printk() is a static inline function, not available
> as an extern.
> Since the purpose of the macro is to print the BUGCHECK info,
> make this config option depend on PRINTK.
>
> Fixes multiple occurrences of this build error:
>
> ../include/linux/printk.h:208:5: error: static declaration of '_printk' follows non-static declaration
>  208 | int _printk(const char *s, ...)
>      |     ^~~~~~~
> In file included from ../arch/ia64/include/asm/cmpxchg.h:5,
> ../arch/ia64/include/uapi/asm/cmpxchg.h:146:28: note: previous declaration of '_printk' with type 'int(const char *, ...)'
>  146 |                 extern int _printk(const char *fmt, ...);
>
> Fixes: 337015573718 ("printk: Userspace format indexing support")

This Fixes tag doesn't make much sense. This was already broken long before 
that patch, just the error message changed: printk() was already static inline 
on !CONFIG_PRINTK for eons.

> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Cc: linux-ia64@xxxxxxxxxxxxxxx
> Cc: Petr Mladek <pmladek@xxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Tony Luck <tony.luck@xxxxxxxxx>
> Cc: Chris Down <chris@xxxxxxxxxxxxxx>
> ---
> arch/ia64/Kconfig.debug |    2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-next-20210917.orig/arch/ia64/Kconfig.debug
> +++ linux-next-20210917/arch/ia64/Kconfig.debug
> @@ -39,7 +39,7 @@ config DISABLE_VHPT
>
> config IA64_DEBUG_CMPXCHG
> 	bool "Turn on compare-and-exchange bug checking (slow!)"
> -	depends on DEBUG_KERNEL
> +	depends on DEBUG_KERNEL && PRINTK
> 	help
> 	  Selecting this option turns on bug checking for the IA-64
> 	  compare-and-exchange instructions.  This is slow!  Itaniums