ARM: OMAP2+: Fix null pointer dereference and memory leak in omap_soc_device_init

kasprintf() returns a pointer to dynamically allocated memory which can
be NULL upon failure. When 'soc_dev_attr->family' is NULL,it'll trigger
the null pointer dereference issue, such as in 'soc_info_show'.

And when 'soc_device_register' fails, it's necessary to release
'soc_dev_attr->family' to avoid memory leaks.

Fixes: 6770b21 ("ARM: OMAP2+: Export SoC information to userspace")
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Message-ID: <20231123145237.609442-1-chentao@kylinos.cn>
Signed-off-by: Tony Lindgren <tony@atomide.com>

Author: KunWuChan

arch/arm/mach-omap2/id.c

@@ -793,11 +793,16 @@ void __init omap_soc_device_init(void)
 
 	soc_dev_attr->machine  = soc_name;
 	soc_dev_attr->family   = omap_get_family();
+	if (!soc_dev_attr->family) {
+		kfree(soc_dev_attr);
+		return;
+	}
 	soc_dev_attr->revision = soc_rev;
 	soc_dev_attr->custom_attr_group = omap_soc_groups[0];
 
 	soc_dev = soc_device_register(soc_dev_attr);
 	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr->family);
 		kfree(soc_dev_attr);
 		return;
 	}