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Message-ID: <4A76D215.1060300@hartkopp.net>
Date: Mon, 03 Aug 2009 14:03:33 +0200
From: Oliver Hartkopp <oliver@...tkopp.net>
To: Dave Young <hidave.darkstar@...il.com>
CC: Alan Cox <alan@...rguk.ukuu.org.uk>,
Marcel Holtmann <marcel@...tmann.org>,
Linux Netdev List <netdev@...r.kernel.org>,
linux-bluetooth@...r.kernel.org
Subject: Re: tty_register_device NULL pointer dereference in 2.6.31-rc4
Dave Young wrote:
> On Sat, Aug 01, 2009 at 11:21:28AM +0200, Oliver Hartkopp wrote:
>>> --- linux-2.6.orig/include/net/bluetooth/rfcomm.h 2009-08-01 10:53:18.000000000 +0800
>>> +++ linux-2.6/include/net/bluetooth/rfcomm.h 2009-08-01 10:55:29.000000000 +0800
>>> @@ -355,7 +355,18 @@ struct rfcomm_dev_list_req {
>>> };
>>>
>>> int rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
>>> +
>>> +#ifdef CONFIG_BT_RFCOMM_TTY
>>> int rfcomm_init_ttys(void);
>>> void rfcomm_cleanup_ttys(void);
>>> -
>>> +#else
>>> +static inline int rfcomm_init_ttys(void)
>>> +{
>>> + return 0;
>>> +}
>>> +static inline int rfcomm_cleanup_ttys(void)
>>> +{
>>> + return 0;
>>> +}
>>> +#endif
>> Just a minor thing:
>>
>> Does rfcomm_cleanup_ttys() return 'int' or is it 'void' ?
>
> Yes it should be void. Thanks for pointing out, here update the patch:
Hi Dave,
the latest approach seems to fit.
I booted about 25+ times without any problems.
Even the upgrade from Debian Lenny to Squeeze did not cause any probs with
bluetooth.
Tested-by: Oliver Hartkopp <oliver@...tkopp.net>
Thanks!
> ---
>
> rfcomm tty may be used before rfcomm_tty_driver initilized,
> The problem is that now socket layer init before tty layer, if userspace
> program do socket callback right here then oops will happen.
>
> reporting in:
> http://marc.info/?l=linux-bluetooth&m=124404919324542&w=2
>
> make 3 changes:
> 1. remove #ifdef in rfcomm/core.c,
> make it blank function when rfcomm tty not selected in rfcomm.h
>
> 2. tune the rfcomm_init error patch to ensure
> tty driver initilized before rfcomm socket usage.
>
> 3. remove __exit for rfcomm_cleanup_sockets
> because above change need call it in a __init function.
>
>
> CC: Alan Cox <alan@...rguk.ukuu.org.uk>
> Reported-by: Oliver Hartkopp <oliver@...tkopp.net>
> Signed-off-by: Dave Young <hidave.darkstar@...il.com>
> --
> include/net/bluetooth/rfcomm.h | 12 +++++++++++-
> net/bluetooth/rfcomm/core.c | 29 ++++++++++++++++++++---------
> net/bluetooth/rfcomm/sock.c | 2 +-
> 3 files changed, 32 insertions(+), 11 deletions(-)
>
> --- linux-2.6.orig/include/net/bluetooth/rfcomm.h 2009-08-01 13:56:53.000000000 +0800
> +++ linux-2.6/include/net/bluetooth/rfcomm.h 2009-08-01 17:24:59.000000000 +0800
> @@ -355,7 +355,17 @@ struct rfcomm_dev_list_req {
> };
>
> int rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
> +
> +#ifdef CONFIG_BT_RFCOMM_TTY
> int rfcomm_init_ttys(void);
> void rfcomm_cleanup_ttys(void);
> -
> +#else
> +static inline int rfcomm_init_ttys(void)
> +{
> + return 0;
> +}
> +static inline void rfcomm_cleanup_ttys(void)
> +{
> +}
> +#endif
> #endif /* __RFCOMM_H */
> --- linux-2.6.orig/net/bluetooth/rfcomm/core.c 2009-08-01 13:56:53.000000000 +0800
> +++ linux-2.6/net/bluetooth/rfcomm/core.c 2009-08-01 13:57:18.000000000 +0800
> @@ -2080,28 +2080,41 @@ static CLASS_ATTR(rfcomm_dlc, S_IRUGO, r
> /* ---- Initialization ---- */
> static int __init rfcomm_init(void)
> {
> + int ret;
> +
> l2cap_load();
>
> hci_register_cb(&rfcomm_cb);
>
> rfcomm_thread = kthread_run(rfcomm_run, NULL, "krfcommd");
> if (IS_ERR(rfcomm_thread)) {
> - hci_unregister_cb(&rfcomm_cb);
> - return PTR_ERR(rfcomm_thread);
> + ret = PTR_ERR(rfcomm_thread);
> + goto out_thread;
> }
>
> if (class_create_file(bt_class, &class_attr_rfcomm_dlc) < 0)
> BT_ERR("Failed to create RFCOMM info file");
>
> - rfcomm_init_sockets();
> -
> -#ifdef CONFIG_BT_RFCOMM_TTY
> - rfcomm_init_ttys();
> -#endif
> + ret = rfcomm_init_ttys();
> + if (ret)
> + goto out_tty;
> +
> + ret = rfcomm_init_sockets();
> + if (ret)
> + goto out_sock;
>
> BT_INFO("RFCOMM ver %s", VERSION);
>
> return 0;
> +
> +out_sock:
> + rfcomm_cleanup_ttys();
> +out_tty:
> + kthread_stop(rfcomm_thread);
> +out_thread:
> + hci_unregister_cb(&rfcomm_cb);
> +
> + return ret;
> }
>
> static void __exit rfcomm_exit(void)
> @@ -2112,9 +2125,7 @@ static void __exit rfcomm_exit(void)
>
> kthread_stop(rfcomm_thread);
>
> -#ifdef CONFIG_BT_RFCOMM_TTY
> rfcomm_cleanup_ttys();
> -#endif
>
> rfcomm_cleanup_sockets();
> }
> --- linux-2.6.orig/net/bluetooth/rfcomm/sock.c 2009-08-01 13:56:53.000000000 +0800
> +++ linux-2.6/net/bluetooth/rfcomm/sock.c 2009-08-01 13:57:18.000000000 +0800
> @@ -1132,7 +1132,7 @@ error:
> return err;
> }
>
> -void __exit rfcomm_cleanup_sockets(void)
> +void rfcomm_cleanup_sockets(void)
> {
> class_remove_file(bt_class, &class_attr_rfcomm);
>
--
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