Re: [Bug #10713] ehci splatter in 2.6.26-rc2

[Lennert Buytenhek <buytenh@wantstofly.org>]

On Sun, May 18, 2008 at 01:13:56PM +0200, Rafael J. Wysocki wrote:

> This message has been generated automatically as a part of a report
> of recent regressions.
> 
> The following bug entry is on the current list of known regressions
> from 2.6.25.  Please verify if it still should be listed.
> 
> 
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=10713
> Subject		: ehci splatter in 2.6.26-rc2
> Submitter	: Lennert Buytenhek <buytenh@wantstofly.org>
> Date		: 2008-05-14 11:24 (5 days old)
> References	: http://marc.info/?l=linux-kernel&amp;m=121076435420129&amp;w=4
> Handled-By	: David Brownell <david-b@pacbell.net>

Just re-checked, and this device (a USB to dual PS/2 cable) works
fine on 2.6.25 on this hardware:

	usb 1-1: new low speed USB device using orion-ehci and address 2
	usb 1-1: configuration #1 chosen from 1 choice
	input: PS2 to USB AdapterA3 as /class/input/input0
	input: USB HID v1.10 Keyboard [PS2 to USB AdapterA3] on usb-orion-ehci.0-1
	input: PS2 to USB AdapterA3 as /class/input/input1
	input: USB HID v1.10 Mouse [PS2 to USB AdapterA3] on usb-orion-ehci.0-1

But on 2.6.26-rc3 it just gives me:

	usb 1-1: new low speed USB device using orion-ehci and address 2
	Unable to handle kernel NULL pointer dereference at virtual address 00000000
	pgd = c0004000
	[00000000] *pgd=00000000
	Internal error: Oops: 5 [#1] PREEMPT
	Modules linked in:
	CPU: 0    Not tainted  (2.6.26-rc3 #347)
	PC is at qh_append_tds+0x24c/0x47c
	LR is at ehci_qtd_alloc+0x30/0x5c
	pc : [<c0242374>]    lr : [<c0241d48>]    psr: 00000093
	sp : c7cfdcb0  ip : c7e3c4c0  fp : c7cfdcfc
	r10: ffc83080  r9 : 00000008  r8 : c7d12240
	r7 : 80000080  r6 : 00000080  r5 : 00000000  r4 : 00000002
	r3 : c7d3f000  r2 : 00000000  r1 : 40800000  r0 : 08085000
	Flags: nzcv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
	Control: 0005317f  Table: 00004000  DAC: 00000017
	Process khubd (pid: 79, stack limit = 0xc7cfc268)
	Stack: (0xc7cfdcb0 to 0xc7cfe000)
	[...]
	Backtrace:
	[<c0242128>] (qh_append_tds+0x0/0x47c) from [<c0243ca0>] (ehci_urb_enqueue+0x100/0xff4)
	[<c0243ba0>] (ehci_urb_enqueue+0x0/0xff4) from [<c0234c30>] (usb_hcd_submit_urb+0x824/0x91c)
	[<c023440c>] (usb_hcd_submit_urb+0x0/0x91c) from [<c0235098>] (usb_submit_urb+0x224/0x260)
	[<c0234e74>] (usb_submit_urb+0x0/0x260) from [<c0235b5c>] (usb_start_wait_urb+0x44/0xac)
	 r6:c7d12240 r5:c7cfde80 r4:00000000
	[<c0235b18>] (usb_start_wait_urb+0x0/0xac) from [<c0235dac>] (usb_control_msg+0xc8/0xec)
	 r8:00000000 r7:00000100 r6:fffffff4 r5:00000040 r4:c7e3dc20
	[<c0235ce4>] (usb_control_msg+0x0/0xec) from [<c0230854>] (hub_port_init+0x274/0x5e4)
	[<c02305e0>] (hub_port_init+0x0/0x5e4) from [<c0231bec>] (hub_thread+0x608/0xc10)
	[<c02315e4>] (hub_thread+0x0/0xc10) from [<c0059e20>] (kthread+0x5c/0x94)
	[<c0059dc4>] (kthread+0x0/0x94) from [<c0047908>] (do_exit+0x0/0x67c)
	 r6:00000000 r5:00000000 r4:00000000
	Code: e51bc040 e5932000 e51c309c e1520003 (15923000)
	---[ end trace ce1992535f2e8e4d ]---
	note: khubd[79] exited with preempt_count 1

If you have no idea what might have caused this to creep in, I guess
I'll have to bisect it?