linux-kernel - [PATCH v2] kernel/module: Fix mem leak in module_add_modinfo

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Date:   Thu, 30 May 2019 21:43:04 +0800
From:   YueHaibing <yuehaibing@...wei.com>
To:     <jeyu@...nel.org>, <gregkh@...uxfoundation.org>
CC:     <linux-kernel@...r.kernel.org>, <paulmck@...ux.ibm.com>,
        YueHaibing <yuehaibing@...wei.com>
Subject: [PATCH v2] kernel/module: Fix mem leak in module_add_modinfo_attrs

In module_add_modinfo_attrs if sysfs_create_file
fails, we forget to free allocated modinfo_attrs
and roll back the sysfs files.

Fixes: 03e88ae1b13d ("[PATCH] fix module sysfs files reference counting")
Signed-off-by: YueHaibing <yuehaibing@...wei.com>
---
v2: free from '--i' instead of 'i--'  
---
 kernel/module.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/kernel/module.c b/kernel/module.c
index 6e6712b..78e21a7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1723,15 +1723,29 @@ static int module_add_modinfo_attrs(struct module *mod)
 		return -ENOMEM;
 
 	temp_attr = mod->modinfo_attrs;
-	for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
+	for (i = 0; (attr = modinfo_attrs[i]); i++) {
 		if (!attr->test || attr->test(mod)) {
 			memcpy(temp_attr, attr, sizeof(*temp_attr));
 			sysfs_attr_init(&temp_attr->attr);
 			error = sysfs_create_file(&mod->mkobj.kobj,
 					&temp_attr->attr);
+			if (error)
+				goto error_out;
 			++temp_attr;
 		}
 	}
+
+	return 0;
+
+error_out:
+	for (; (attr = &mod->modinfo_attrs[i]) && i >= 0; --i) {
+		if (!attr->attr.name)
+			break;
+		sysfs_remove_file(&mod->mkobj.kobj, &attr->attr);
+		if (attr->free)
+			attr->free(mod);
+	}
+	kfree(mod->modinfo_attrs);
 	return error;
 }
 
-- 
2.7.4