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From: Petr Pavlu <petr.pavlu@suse.com>
To: Luis Chamberlain <mcgrof@kernel.org>,
	Petr Pavlu <petr.pavlu@suse.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Daniel Gomez <da.gomez@samsung.com>
Cc: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org,
	Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH 4/5] tracing: Replace MAX_PARAM_PREFIX_LEN with MODULE_NAME_LEN
Date: Mon, 30 Jun 2025 16:32:35 +0200	[thread overview]
Message-ID: <20250630143535.267745-5-petr.pavlu@suse.com> (raw)
In-Reply-To: <20250630143535.267745-1-petr.pavlu@suse.com>

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


  parent reply	other threads:[~2025-06-30 14:36 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-30 14:32 [PATCH 0/5] module: Fix minor problems related to MODULE_NAME_LEN Petr Pavlu
2025-06-30 14:32 ` [PATCH 1/5] module: Prevent silent truncation of module name in delete_module(2) Petr Pavlu
2025-07-16 19:47   ` Daniel Gomez
2025-06-30 14:32 ` [PATCH 2/5] module: Remove unnecessary +1 from last_unloaded_module::name size Petr Pavlu
2025-07-16 19:49   ` Daniel Gomez
2025-06-30 14:32 ` [PATCH 3/5] module: Restore the moduleparam prefix length check Petr Pavlu
2025-07-17 19:23   ` Daniel Gomez
2025-07-21  9:21     ` Petr Pavlu
2025-07-28  6:43       ` Daniel Gomez
2025-06-30 14:32 ` Petr Pavlu [this message]
2025-07-28  6:48   ` [PATCH 4/5] tracing: Replace MAX_PARAM_PREFIX_LEN with MODULE_NAME_LEN Daniel Gomez
2025-07-28 14:34     ` Steven Rostedt
2025-06-30 14:32 ` [PATCH 5/5] module: Rename MAX_PARAM_PREFIX_LEN to __MODULE_NAME_LEN Petr Pavlu
2025-07-28  6:48   ` Daniel Gomez
2025-07-31 12:03 ` [PATCH 0/5] module: Fix minor problems related to MODULE_NAME_LEN Daniel Gomez

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