Use the MODULE_NAME_LEN definition in module_exists() to obtain the maximum
size of a module name, instead of using MAX_PARAM_PREFIX_LEN. The values
are the same but MODULE_NAME_LEN is more appropriate in this context.
MAX_PARAM_PREFIX_LEN was added in commit 730b69d22525 ("module: check
kernel param length at compile time, not runtime") only to break a circular
dependency between module.h and moduleparam.h, and should mostly be limited
to use in moduleparam.h.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
---

As a side note, I suspect the function module_exists() would be better
replaced with !!find_module() + RCU locking, but that is a separate issue.

 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 95ae7c4e5835..b9da0c4661a0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -10373,7 +10373,7 @@ bool module_exists(const char *module)
 {
 	/* All modules have the symbol __this_module */
 	static const char this_mod[] = "__this_module";
-	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
+	char modname[MODULE_NAME_LEN + sizeof(this_mod) + 2];
 	unsigned long val;
 	int n;
 
-- 
2.49.0

On 30/06/2025 16.32, Petr Pavlu wrote:
> Use the MODULE_NAME_LEN definition in module_exists() to obtain the maximum
> size of a module name, instead of using MAX_PARAM_PREFIX_LEN. The values
> are the same but MODULE_NAME_LEN is more appropriate in this context.
> MAX_PARAM_PREFIX_LEN was added in commit 730b69d22525 ("module: check
> kernel param length at compile time, not runtime") only to break a circular
> dependency between module.h and moduleparam.h, and should mostly be limited
> to use in moduleparam.h.
> 
> Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>

Steven, Masami,

I'm planning to merge these series into modules-next. I think and Ack/Review
would be great from you. Otherwise, let me know if you'd rather take this patch
through tracing instead (in case it looks good from your side).

> ---
> 
> As a side note, I suspect the function module_exists() would be better
> replaced with !!find_module() + RCU locking, but that is a separate issue.
> 
>  kernel/trace/trace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 95ae7c4e5835..b9da0c4661a0 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -10373,7 +10373,7 @@ bool module_exists(const char *module)
>  {
>  	/* All modules have the symbol __this_module */
>  	static const char this_mod[] = "__this_module";
> -	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
> +	char modname[MODULE_NAME_LEN + sizeof(this_mod) + 2];
>  	unsigned long val;
>  	int n;
>  

LGTM,

Reviewed-by: Daniel Gomez <da.gomez@samsung.com>

On Mon, 28 Jul 2025 08:48:01 +0200
Daniel Gomez <da.gomez@kernel.org> wrote:

> On 30/06/2025 16.32, Petr Pavlu wrote:
> > Use the MODULE_NAME_LEN definition in module_exists() to obtain the maximum
> > size of a module name, instead of using MAX_PARAM_PREFIX_LEN. The values
> > are the same but MODULE_NAME_LEN is more appropriate in this context.
> > MAX_PARAM_PREFIX_LEN was added in commit 730b69d22525 ("module: check
> > kernel param length at compile time, not runtime") only to break a circular
> > dependency between module.h and moduleparam.h, and should mostly be limited
> > to use in moduleparam.h.
> > 
> > Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
> > Cc: Steven Rostedt <rostedt@goodmis.org>
> > Cc: Masami Hiramatsu <mhiramat@kernel.org>  
> 
> Steven, Masami,
> 
> I'm planning to merge these series into modules-next. I think and Ack/Review
> would be great from you. Otherwise, let me know if you'd rather take this patch
> through tracing instead (in case it looks good from your side).

Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>

> 
> > ---
> > 
> > As a side note, I suspect the function module_exists() would be better
> > replaced with !!find_module() + RCU locking, but that is a separate issue.

Yeah, that is probably something that should be done too.

Thanks,

-- Steve