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Commit 63662139 authored by David Woodhouse's avatar David Woodhouse
Browse files

params: Fix potential memory leak in add_sysfs_param() 



On allocation failure, it would fail to free the old attrs array which
was no longer referenced by anything (since it would free the old
module_param_attrs struct on the way out).

Comment the suspicious-looking krealloc() usage to explain why it *isn't*
actually buggy, despite looking like a classic realloc() usage bug.

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent fe9ab00f

kernel/params.c

+4 −1
Original line number Diff line number Diff line
@@ -613,10 +613,13 @@ static __modinit int add_sysfs_param(struct module_kobject *mk, 
		       sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),

		       GFP_KERNEL);

	if (!new) {

		kfree(mk->mp);

		kfree(attrs);

		err = -ENOMEM;

		goto fail;

	}

	/* Despite looking like the typical realloc() bug, this is safe.

	 * We *want* the old 'attrs' to be freed either way, and we'll store

	 * the new one in the success case. */

	attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);

	if (!attrs) {

		err = -ENOMEM;