Re: tty_register_device NULL pointer dereference in 2.6.31-rc4
From: Oliver Hartkopp <hidden>
Date: 2009-08-01 09:15:24
Also in:
linux-bluetooth
Dave Young wrote:
On Fri, Jul 31, 2009 at 01:20:19PM +0200, Oliver Hartkopp wrote:
quoted
applied this patch and replaced mdelay(100) with msleep(100). I got two crashes and three proper boots. The crashes look like the formerly posted screenshots. When it boots properly i can see the delay in the boot process. Does this help?Yes, I think so. Please unapply the before two patch, try the following v2 patch instead. Changes from v1: fixes 'goto' path again, make tty init before sock init.
Hi Dave, i did a 'git reset --hard' to get back to vanilla 2.6.31-rc4 . Applied the v2 patch and booted five times without any problems. I'll keep you informed if anything changes ;-) Thanks, Oliver
quoted hunk ↗ jump to hunk
--- 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 <redacted> Reported-by: Oliver Hartkopp <redacted> Signed-off-by: Dave Young <redacted> -- include/net/bluetooth/rfcomm.h | 13 ++++++++++++- net/bluetooth/rfcomm/core.c | 29 ++++++++++++++++++++--------- net/bluetooth/rfcomm/sock.c | 2 +- 3 files changed, 33 insertions(+), 11 deletions(-)--- 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 #endif /* __RFCOMM_H */ --- linux-2.6.orig/net/bluetooth/rfcomm/core.c 2009-08-01 10:53:18.000000000 +0800 +++ linux-2.6/net/bluetooth/rfcomm/core.c 2009-08-01 11:03:24.000000000 +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 10:53:18.000000000 +0800 +++ linux-2.6/net/bluetooth/rfcomm/sock.c 2009-08-01 10:55:29.000000000 +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);