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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hulk Robot <hulkci@huawei.com>,
        Wang Hai <wanghai38@huawei.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 037/320] Bluetooth: cmtp: fix possible panic when cmtp_init_sockets() fails
Date:   Mon, 24 Jan 2022 19:40:21 +0100
Message-Id: <20220124183955.010672799@linuxfoundation.org>
In-Reply-To: <20220124183953.750177707@linuxfoundation.org>
References: <20220124183953.750177707@linuxfoundation.org>
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From: Wang Hai <wanghai38@huawei.com>

[ Upstream commit 2a7ca7459d905febf519163bd9e3eed894de6bb7 ]

I got a kernel BUG report when doing fault injection test:

------------[ cut here ]------------
kernel BUG at lib/list_debug.c:45!
...
RIP: 0010:__list_del_entry_valid.cold+0x12/0x4d
...
Call Trace:
 proto_unregister+0x83/0x220
 cmtp_cleanup_sockets+0x37/0x40 [cmtp]
 cmtp_exit+0xe/0x1f [cmtp]
 do_syscall_64+0x35/0xb0
 entry_SYSCALL_64_after_hwframe+0x44/0xae

If cmtp_init_sockets() in cmtp_init() fails, cmtp_init() still returns
success. This will cause a kernel bug when accessing uncreated ctmp
related data when the module exits.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bluetooth/cmtp/core.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/bluetooth/cmtp/core.c b/net/bluetooth/cmtp/core.c
index 0a2d78e811cf5..83eb84e8e688f 100644
--- a/net/bluetooth/cmtp/core.c
+++ b/net/bluetooth/cmtp/core.c
@@ -501,9 +501,7 @@ static int __init cmtp_init(void)
 {
 	BT_INFO("CMTP (CAPI Emulation) ver %s", VERSION);
 
-	cmtp_init_sockets();
-
-	return 0;
+	return cmtp_init_sockets();
 }
 
 static void __exit cmtp_exit(void)
-- 
2.34.1