On Fri, 28 Sep 2007 18:32:32 +0200, Pierre-Yves Paulus <[EMAIL PROTECTED]> wrote:
This looks more informational, thanks. > DEV: Unregistering device. ID = 'rfcomm0' > PM: Removing info for No Bus:rfcomm0 > kobject_uevent_env > fill_kobj_path: path = '/class/tty/rfcomm0' > fill_kobj_path: path = > '/devices/pci0000:00/0000:00:0f.4/usb1/1-1/1-1.5/1-1.5.1/1-1.5.1:1.0/hci2/acl00126253F906' > kobject rfcomm0: cleaning up > device_create_release called for rfcomm0 Here rfcomm0 was unregistered and released. > bus bluetooth: remove device acl00126253F906 > PM: Removing info for bluetooth:acl00126253F906 > kobject_uevent_env > fill_kobj_path: path = > '/devices/pci0000:00/0000:00:0f.4/usb1/1-1/1-1.5/1-1.5.1/1-1.5.1:1.0/hci2/acl00126253F906' > kobject acl00126253F906: cleaning up And here the corresponding physdev. > BUG: unable to handle kernel NULL pointer dereference at virtual address > 00000000 > printing eip: > c0249e29 > *pde = 00000000 > Oops: 0000 [#1] > Modules linked in: rfcomm l2cap battery ipv6 dm_snapshot dm_mirror > dm_mod softdog loop parport_pc parport floppy rtc pcspkr ac button > psmouse serio_raw snd_cs5535audio snd_ac97_codec ac97_bus snd_pcm > snd_timer snd soundcore snd_page_alloc geode_rng cs5535_gpio hci_usb > bluetooth geode_aes blkcipher tsdev evdev usbhid hid reiserfs ide_disk > generic amd74xx ide_core ohci_hcd sata_via ata_generic 8139cp libata > 8139too usbcore mii scsi_mod thermal processor fan > CPU: 0 > EIP: 0060:[<c0249e29>] Not tainted VLI > EFLAGS: 00010017 (2.6.23-rc8 #1) > EIP is at skb_dequeue+0x23/0x4a > eax: 00000282 ebx: 00000282 ecx: 00000000 edx: caf8ab8c > esi: c8428d48 edi: c8428c00 ebp: c8428c0c esp: c124ff60 > ds: 007b es: 007b fs: 0000 gs: 0000 ss: 0068 > Process events/0 (pid: 5, ti=c124e000 task=c1243500 task.ti=c124e000) > Stack: caf8ab8c c024b0a1 c8428c00 d02f4075 c8428d60 c020eb8d c08978a8 > 00000000 > 00000000 00000000 cf7ab680 c8428d48 c020eac4 00000000 c01279a9 > c124ffb4 > 00000046 c1243500 cf7ab680 cf7ab680 c0127ffe c124ffd0 c01280b0 > 00000000 > Call Trace: > [<c024b0a1>] skb_queue_purge+0x11/0x17 > [<d02f4075>] rfcomm_tty_flush_buffer+0x1c/0x33 [rfcomm] > [<c020eb8d>] do_tty_hangup+0xc9/0x2d0 > [<c020eac4>] do_tty_hangup+0x0/0x2d0 > [<c01279a9>] run_workqueue+0x7d/0x103 > [<c0127ffe>] worker_thread+0x0/0xbe > [<c01280b0>] worker_thread+0xb2/0xbe > [<c012a510>] autoremove_wake_function+0x0/0x35 > [<c012a363>] kthread+0x36/0x5b > [<c012a32d>] kthread+0x0/0x5b > [<c0104e17>] kernel_thread_helper+0x7/0x10 > ======================= rfcomm0 is already freed, maybe this code is still trying to access it? > Code: 89 42 0a 5b 5e 5f 5d c3 53 89 c2 9c 58 90 8d b4 26 00 00 00 00 89 > c3 fa 90 8d b4 26 00 00 00 00 90 8b 0a 39 d1 75 04 31 c9 eb 17 <8b> 01 > ff 4a 08 89 02 89 50 04 c7 01 00 00 00 00 c7 41 04 00 00 > EIP: [<c0249e29>] skb_dequeue+0x23/0x4a SS:ESP 0068:c124ff60 > WARNING: at lib/kref.c:33 kref_get() > [<c01c6db7>] kref_get+0x34/0x3d > [<c01c61a9>] kobject_get+0xf/0x13 > [<c022578d>] get_device+0xe/0x14 > [<c02257a6>] device_move+0x13/0x114 > [<d02f4b7c>] rfcomm_tty_close+0x23/0x61 [rfcomm] > [<c020f88d>] release_dev+0x1c0/0x54e > [<d02f40e5>] rfcomm_dev_destruct+0x59/0x65 [rfcomm] > [<d02f4725>] rfcomm_dev_ioctl+0x329/0x4d0 [rfcomm] > [<c0130c96>] tick_program_event+0x2a/0x49 > [<c0248124>] release_sock+0xc/0x74 > [<c020fc22>] tty_release+0x7/0xa > [<c015dabd>] __fput+0x93/0x147 > [<c015b66a>] filp_close+0x51/0x58 > [<c02a8b0e>] __sched_text_start+0x1d6/0x245 > [<c015c70b>] sys_close+0x54/0x83 > [<c0103c72>] syscall_call+0x7/0xb > ======================= > DEVICE: moving 'rfcomm0' to '<NULL>' > kobject <NULL>: cleaning up > device_create_release called for rfcomm0 But here someone still tries to move rfcomm0 around? It already is gone and released... The code path has no reference on rfcomm0. (Well, device_move() tries to get a reference on the device to be moved, but that doesn't help since the device is already gone.) This looks like a race inside rfcomm. The device_unregister() either needs to be delayed until after device_move() has finished, or the thread calling device_move() needs to have a reference. (device_move() on an unregistered device should just fail but not oops.) Marcel? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
