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From:   Wang Hai <wanghai38@huawei.com>
To:     <isdn@linux-pingi.de>, <marcel@holtmann.org>,
        <johan.hedberg@gmail.com>, <luiz.dentz@gmail.com>,
        <davem@davemloft.net>, <kuba@kernel.org>, <cascardo@canonical.com>
CC:     <netdev@vger.kernel.org>, <linux-bluetooth@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH v2] Bluetooth: cmtp: fix possible panic when cmtp_init_sockets() fails
Date:   Mon, 25 Oct 2021 21:10:12 +0800
Message-ID: <20211025131012.2771062-1-wanghai38@huawei.com>
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Precedence: bulk

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>
---
v1->v2: remove the temporary variable "err"
 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 0a2d78e811cf..83eb84e8e688 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)
-- 
2.25.1