From 67e40054de86aae520ddc2a072d7f6951812a14f Mon Sep 17 00:00:00 2001
From: Qinglang Miao <miaoqinglang@huawei.com>
Date: Fri, 15 Jan 2021 10:22:50 +0800
Subject: [PATCH] ACPI: configfs: add missing check after configfs_register_default_group()
Git-commit: 67e40054de86aae520ddc2a072d7f6951812a14f
Patch-mainline: v5.12-rc1
References: git-fixes

A list_add corruption is reported by Hulk Robot like this:
==============
list_add corruption.
Call Trace:
link_obj+0xc0/0x1c0
link_group+0x21/0x140
configfs_register_subsystem+0xdb/0x380
acpi_configfs_init+0x25/0x1000 [acpi_configfs]
do_one_initcall+0x149/0x820
do_init_module+0x1ef/0x720
load_module+0x35c8/0x4380
__do_sys_finit_module+0x10d/0x1a0
do_syscall_64+0x34/0x80

It's because of the missing check after configfs_register_default_group,
where configfs_unregister_subsystem should be called once failure.

Fixes: 612bd01fc6e0 ("ACPI: add support for loading SSDTs via configfs")
Reported-by: Hulk Robot <hulkci@huawei.com>
Suggested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/acpi/acpi_configfs.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
index cf91f49101ea..3a14859dbb75 100644
--- a/drivers/acpi/acpi_configfs.c
+++ b/drivers/acpi/acpi_configfs.c
@@ -268,7 +268,12 @@ static int __init acpi_configfs_init(void)
 
 	acpi_table_group = configfs_register_default_group(root, "table",
 							   &acpi_tables_type);
-	return PTR_ERR_OR_ZERO(acpi_table_group);
+	if (IS_ERR(acpi_table_group)) {
+		configfs_unregister_subsystem(&acpi_configfs);
+		return PTR_ERR(acpi_table_group);
+	}
+
+	return 0;
 }
 module_init(acpi_configfs_init);
 
-- 
2.26.2