2.6.7 and rfcomm Oops (BlueTooth)

I just managed to start using my phone for ppp via BlueTooth with 2.6.7 (stock + kmsgdump patch).

Sometimes I get the foolowing Oops though:

Bluetooth: RFCOMM ver 1.3
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM TTY layer initialized

Unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
00000000
*pde = 00000000
Oops: 0000 [#1]
PREEMPT 
Modules linked in: rfcomm l2cap hci_usb bluetooth usbhid 3c59x nvidia ehci_hcd ohci_hcd usbcore ipv6
CPU:    0
EIP:    0060:[<00000000>]    Tainted: P  
EFLAGS: 00210202   (2.6.7-KK1_sata) 

EIP is at 0x0
eax: 00000000 ebx: d5500000 ecx: e0c7f5c0 edx: 00000000
esi: da66cf58 edi: c0000000 ebp: 00000000 esp: d5501eb4
ds: 007b es: 007b ss: 0068
Process rfcomm (pid: 9368, threadinfo=d5500000 task=dd5f6830)

Stack: e0c7654e da66cf58 00000000 d5500000 e0c7f5c0 e0c76617 da66cf58 00000000 
       da66c3d8 d210b000 cfdac7e0 e0c7ade7 da66cf58 00000000 d210b000 00000000 
       c0259dcb d210b000 cfdac7e0 00000000 00200286 00000000 026524f0 026524f0 
Call Trace:
 [<e0c7654e>] __rfcomm_dlc_close+0x4e/0xd0 [rfcomm]
 [<e0c76617>] rfcomm_dlc_close+0x47/0x70 [rfcomm]
 [<e0c7ade7>] rfcomm_tty_close+0x67/0xb0 [rfcomm]
 [<c0259dcb>] release_dev+0x60b/0x620
 [<c016552f>] do_pollfd+0x4f/0x90
 [<c01655da>] do_poll+0x6a/0xd0
 [<c025a140>] tty_release+0x0/0x60
 [<c025a16a>] tty_release+0x2a/0x60
 [<c0152d64>] __fput+0x114/0x130
 [<c0151429>] filp_close+0x59/0x90
 [<c01514c1>] sys_close+0x61/0xa0
 [<c0106087>] syscall_call+0x7/0xb

Code:  Bad EIP value.
 <6>note: rfcomm[9368] exited with preempt_count 2

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Hi Kalin,

what the hell is causing this? I didn't changed anything in the RFCOMM TTY layer. Please disable preempt support and try again.

Regards

Marcel

[snip oops]

Well, no idea. The keyword here is "sometimes"...

I'll try to find a better way to reproduce this and report again with/without preempt. AFAIR, last time I got this when I "abruptly" stopped the BT stack on my phone, while using rfcomm for ppp.

Just in case, I updated to bluez-{libs,utils}-2.7, but still got one Oops (essentially the same).

These days I'll have to use the phone and a laptop, but will be away. If I found out something more will post it.

Kalin.

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