Re: Regression: EEE PC hangs when booting off battery

[Alan Jenkins <alan-jenkins-cCz0Lq7MMjm9FHfhHBbuYA@public.gmane.org>]

Kristoffer Ericson wrote:
> On Sat, 11 Apr 2009 10:41:35 +0100
> Alan Jenkins <alan-jenkins-cCz0Lq7MMjm9FHfhHBbuYA@public.gmane.org> wrote:
>
>   
>> Regression #6 on latest git! (last known good is 2.6.29-rc8)
>>
>> My EEE PC hangs on bootup if it is not connected to mains power.  The
>> hang happens during udev coldplug.  I've left it for >60 seconds with
>> nmi_watchdog=1, soft lockup and hung task detection are enabled, and I
>> get no trace.  Key presses are not echoed to the screen.
>>     
>
> Getting this myself, even if power cord attached. Its an tainted
> kernel though (archlinux 2.6.28) so wasnt sure if
> vanilla was affected.
>
> BUG: unable to handle kernel NULL pointer dereference at 00000000
> IP: [<f850d031>] acpi_ac_get_state+0x1b/0x59 [ac]
> *pde = 00000000
> Oops: 0000 [#1] PREEMPT SMP
> last sysfs file: /sys/devices/platform/i8042/modalias
> Modules linked in: joydev psmouse snd_pcsp serio_raw i2c_i801 iTCO_wdt iTCO_vendor_support i2c_core uvcvideo compat_ioctl32 videodev v4l1_compat sg option usbserial video output eeepc_laptop rfkill intel_agp agpgart thermal processor fan evdev button battery ac snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_hda_intel snd_hwdep snd_pcm_oss snd_pcm snd_timer snd_page_alloc snd_mixer_oss snd soundcore ath_pci wlan ath_hal(P) arc4 ecb ath5k mac80211 led_class cfg80211 atl2 rtc_cmos rtc_core rtc_lib ext3 jbd mbcache usbhid hid usb_storage sd_mod uhci_hcd ehci_hcd usbcore ata_piix ahci ata_generic pata_acpi libata scsi_mod
>
> Pid: 1794, comm: fsck.ext3 Tainted: P           (2.6.28-ARCH #1) 701
> EIP: 0060:[<f850d031>] EFLAGS: 00010246 CPU: 0
> EIP is at acpi_ac_get_state+0x1b/0x59 [ac]
> EAX: f69559dc EBX: 00000000 ECX: 00000000 EDX: f850d418
> ESI: f6955980 EDI: 00000001 EBP: f6834480 ESP: f6853f0c
>  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> Process fsck.ext3 (pid: 1794, ti=f6852000 task=f737e400 task.ti=f6852000)
> Stack:
>  f69559dc f6955980 f692e360 f850d2fd 00000001 f692e360 c01ab0e0 00000400
>  b80cb000 f6834480 f692e380 00000000 00000000 00000001 00000000 00000000
>  f7327c00 fffffffb c01aafb0 f6834480 c01cead4 f6853fa0 00000400 b80cb000
> Call Trace:
>  [<f850d2fd>] acpi_ac_seq_show+0x12/0x5d [ac]
>  [<c01ab0e0>] seq_read+0x130/0x2e0
>  [<c01aafb0>] seq_read+0x0/0x2e0
>  [<c01cead4>] proc_reg_read+0x64/0xa0
>  [<c01cea70>] proc_reg_read+0x0/0xa0
>  [<c019346d>] vfs_read+0x9d/0x160
>  [<c0193601>] sys_read+0x41/0x80
>  [<c0103f13>] sysenter_do_call+0x12/0x33
>  [<c0320000>] serial_pnp_probe+0x150/0x250
> Code: b8 ea ff ff ff 75 07 8b 43 5c 89 01 31 c0 5b c3 56 89 c6 85 f6 b8 ea ff ff ff 53 74 49 8b 5e 58 8d 46 5c 31 c9 50 ba 18 d4 50 f8 <8b> 03 e8 e0 be d2 c7 89 c2 58 31 c0 85 d2 74 2b 68 1d d4 50 f8
> EIP: [<f850d031>] acpi_ac_get_state+0x1b/0x59 [ac] SS:ESP 0068:f6853f0c
> ---[ end trace eb12d69e27c56472 ]---
>   

I'm pretty sure that's a separate bug :-).  As you say, it happens under
different circumstances, it's a BUG as opposed to a hang, and it's in a
different version (I didn't have my problem in 2.6.28).

www.kerneloops.org says no-one else has reported your bug.  So maybe
you're right, and Arch have applied some patches which nobody else runs
with.  I don't know how to find Arch source packages, so I can't really
tell.

But the only _taint_ as such is due to the ath_hal module.  Let's see,
Arch linux...

<http://wiki.archlinux.org/index.php/Udev#Blacklisting_Modules>
describes how you can (reversibly) blacklist modules.  If you blacklist
ath_pci (and ath_hal too, just to make sure), you could boot without any
taint and generate a "clean" backtrace.

Regards
Alan