linux-kernel - [PATCH] module: print module name on refcount error

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Date:   Mon, 26 Jun 2023 12:32:52 +0200
From:   Jean Delvare <jdelvare@...e.de>
To:     Luis Chamberlain <mcgrof@...nel.org>
Cc:     Michal Hocko <mhocko@...e.com>, linux-modules@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] module: print module name on refcount error

If module_put() triggers a refcount error, include the culprit
module name in the warning message, to easy further investigation of
the issue.

Signed-off-by: Jean Delvare <jdelvare@...e.de>
Suggested-by: Michal Hocko <mhocko@...e.com>
Cc: Luis Chamberlain <mcgrof@...nel.org>
---
 kernel/module/main.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- linux-6.3.orig/kernel/module/main.c
+++ linux-6.3/kernel/module/main.c
@@ -850,7 +850,9 @@ void module_put(struct module *module)
 	if (module) {
 		preempt_disable();
 		ret = atomic_dec_if_positive(&module->refcnt);
-		WARN_ON(ret < 0);	/* Failed to put refcount */
+		WARN(ret < 0,
+		     KERN_WARNING "Failed to put refcount for module %s\n",
+		     module->name);
 		trace_module_put(module, _RET_IP_);
 		preempt_enable();
 	}


-- 
Jean Delvare
SUSE L3 Support