[ltt-dev] kernel bug in the Lttng branch

[Mathieu Desnoyers]

* royer fabien (royerfa at yahoo.fr) wrote:
> HI,
> 
> I am using the Beagle board using an ARM cortexA8 prosessor.
> I found one annoying issue while using lttv-gui. The issue is that my ethernet connection is always disconnected after exporting the DISPLAY and examining the trace.
> 
> The beagle board doens't have a display so you need to export thought the ethernet. And the Beagleboard doesn't have an ethernet port so you need to use the USB host and plug a usb2eth adaptor.
> 

It looks like a mainline bug. Can you reproduce it on the mainline
kernel without the lttng patchset ? If yes, then it should be reported
to lkml and/or omap developers.

Also, knowing the lttng branch you are using would be useful in this bug
report.

Thanks,

Mathieu

> I am using the git : git://git.kernel.org/pub/scm/linux/kernel/git/compudj/linux-2.6-lttng.git
> config: /arch/arm/config/omap3_beagle_defconfig
> 
> From my investigation the file Drivers/usb/core/hub.c line 3343 must be buggy but I didnot find the bug myself. So I am asking for help.
> 
> Oops errror found:
> 
> root at beagleboard:~# hub 1-0:1.0: port 2 disabled by hub (EMI?), re-enabling...
> Unable to handle kernel NULL pointer dereference at virtual address 00000034
> pgd = c0004000
> [00000034] *pgd=00000000
> Internal error: Oops: 17 [#1]
> last sysfs file: /sys/devices/platform/i2c_omap.3/i2c-3/i2c-dev/i2c-3/uevent
> Modules linked in:
> CPU: 0    Not tainted  (2.6.33.1-ga0ff4c3 #6)
> PC is at usb_hcd_unlink_urb+0x48/0x6c
> LR is at kobject_get+0x14/0x1c
> pc : [<c022cfcc>]    lr : [<c01a9fdc>]    psr: 60000013
> sp : cf90be98  ip : 00000004  fp : cfbb4c00
> r10: cfbb4de0  r9 : cfbc8000  r8 : cf930324
> r7 : fffffffe  r6 : 60000013  r5 : 00000000  r4 : cf3c5240
> r3 : 00000000  r2 : fffffffe  r1 : cf3c5240  r0 : cf990400
> Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
> Control: 10c5387d  Table: 8f3bc019  DAC: 00000017
> Process khubd (pid: 131, stack limit = 0xcf90a2e8)
> Stack: (0xcf90be98 to 0xcf90c000)
> be80:                                                       cf3c524c cf3c5240
> bea0: cf930318 cf930324 cfbc8000 c022db84 cf3c5240 cf930324 cfbc8000 c022c870
> bec0: cf3c5240 cf930318 cf3c5240 cf930318 cf930324 c022c928 cf990400 cf930318
> bee0: 00000001 cf99047c cf990468 c022e600 cf990400 00000003 0000001f c022e62c
> bf00: cf990400 cf99049c 0000001f c022a034 cf9246c0 00000002 00000002 cfbb4c00
> bf20: 00000501 cfbc8000 ffffffed c022a6fc cf90bf64 cf8e9270 cf8e9270 00000001
> bf40: cf9247e0 cf99049c cf9247e0 00000002 00000001 cfbb4c04 cf9246c1 00000000
> bf60: cf90a000 cf924704 cf9247c0 cf92470c cf92475c cf9246c8 cfbb4c9c 00000009
> bf80: cf924708 cf924700 00000000 cf8e9240 c006dc58 cf90bf94 cf90bf94 c0072394
> bfa0: 05010002 cf90a000 cf90bfcc cf823f68 cf90bfd4 c022a2bc 00000000 00000000
> bfc0: 00000000 00000000 00000000 c006d854 00000000 00000000 cf90bfd8 cf90bfd8
> bfe0: 00000000 00000000 00000000 00000000 00000000 c002ddac 00000000 00000000
> [<c022cfcc>] (usb_hcd_unlink_urb+0x48/0x6c) from [<c022db84>] (usb_kill_urb+0x48/0xec)
> [<c022db84>] (usb_kill_urb+0x48/0xec) from [<c022c928>] (usb_hcd_flush_endpoint+0xac/0xc4)
> [<c022c928>] (usb_hcd_flush_endpoint+0xac/0xc4) from [<c022e600>] (usb_disable_endpoint+0x6c/0x84)
> [<c022e600>] (usb_disable_endpoint+0x6c/0x84) from [<c022e62c>] (usb_disable_device+0x14/0xf0)
> [<c022e62c>] (usb_disable_device+0x14/0xf0) from [<c022a034>] (usb_disconnect+0x88/0xe0)
> [<c022a034>] (usb_disconnect+0x88/0xe0) from [<c022a6fc>] (hub_thread+0x440/0xe38)
> [<c022a6fc>] (hub_thread+0x440/0xe38) from [<c006d854>] (kthread+0x78/0x80)
> [<c006d854>] (kthread+0x78/0x80) from [<c002ddac>] (kernel_thread_exit+0x0/0x8)
> Code: 1a000009 e5943028 e1a02007 e1a01004 (e5930034)
> ---[ end trace ec79f3ceae39486f ]---
> 
> 
> 
>       
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-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com