Message-ID: <45F7D922.6010501@s5r6.in-berlin.de>
Date:	Wed, 14 Mar 2007 12:14:42 +0100
From:	Stefan Richter <stefanr@...6.in-berlin.de>
To:	Ismail Dönmez <ismail@...dus.org.tr>
CC:	linux-kernel@...r.kernel.org,
	linux1394-devel@...ts.sourceforge.net, Greg KH <greg@...ah.com>
Subject: oops in __nodemgr_remove_host_dev (was Re: Ooops with suspend to
 RAM)

(Cc'ing Greg KH and linux1394-devel)

Ismail Dönmez wrote at lkml:
> With latest GIT tree I am getting the following oops when I try to suspend to 
> RAM:
> 
> BUG: unable to handle kernel NULL pointer dereference at virtual address 
> 00000094
>  printing eip:
> c0222af4
> *pde = 00000000
> Oops: 0000 [#1]
> PREEMPT
> Modules linked in: i915 drm snd_pcm_oss snd_mixer_oss snd_seq_dummy 
> snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device usbhid eth1394 ipw2200 
> ieee80211 ieee80211_crypt snd_hda_intel snd_hda_codec snd_pcm snd_timer snd 
> snd_page_alloc tifm_7xx1 tifm_core i2c_i801 i2c_core ehci_hcd uhci_hcd 
> ohci1394 ieee1394 pcmcia usbcore yenta_socket rsrc_nonstatic pcmcia_core 
> sony_laptop backlight
> CPU:    0
> EIP:    0060:[<c0222af4>]    Not tainted VLI
> EFLAGS: 00010246   (2.6.21-rc3 #12)
> EIP is at class_device_remove_attrs+0xa/0x30
> eax: f7cb5b18   ebx: 00000000   ecx: f8bde010   edx: 00000000
> esi: 00000000   edi: f7cb5b18   ebp: 00000000   esp: d93e7e1c
> ds: 007b   es: 007b   fs: 00d8  gs: 0033  ss: 0068
> Process modprobe (pid: 12200, ti=d93e6000 task=e5770a50 task.ti=d93e6000)
> Stack: f7cb5b18 f7cb5b20 00000000 c0222bc3 f7cb5990 00000000 f7cb5b18 f7cb59c4
>        f8bcdc0f 00000000 c0222bfb f7cb5990 f8bcdbf6 f8bd3275 04e2c100 0000000f
>        000003c3 f8dcf05f 00000000 f7e3e000 00000000 f8bcdc17 c0220567 f7e3e0a4
> Call Trace:
>  [<c0222bc3>] class_device_del+0xa9/0xd9
>  [<f8bcdc0f>] __nodemgr_remove_host_dev+0x0/0xb [ieee1394]
>  [<c0222bfb>] class_device_unregister+0x8/0x10
>  [<f8bcdbf6>] nodemgr_remove_ne+0x61/0x7a [ieee1394]
>  [<f8dcf05f>] ether1394_mac_addr+0x0/0x12 [eth1394]
>  [<f8bcdc17>] __nodemgr_remove_host_dev+0x8/0xb [ieee1394]
>  [<c0220567>] device_for_each_child+0x1a/0x3c
>  [<f8bcdf34>] nodemgr_remove_host+0x30/0x90 [ieee1394]
>  [<f8bcb4b1>] __unregister_host+0x1a/0xac [ieee1394]
>  [<c0125e1c>] flush_cpu_workqueue+0x98/0xb7
>  [<f8bcb6da>] highlevel_remove_host+0x21/0x42 [ieee1394]
>  [<f8bcb247>] hpsb_remove_host+0x37/0x58 [ieee1394]
>  [<f8be1229>] ohci1394_pci_remove+0x47/0x1ec [ohci1394]
>  [<c01877b9>] sysfs_hash_and_remove+0xfa/0x111
>  [<c01ccc9c>] pci_device_remove+0x16/0x35
>  [<c0222321>] __device_release_driver+0x6e/0x8b
>  [<c022279b>] driver_detach+0x99/0xda
>  [<c0221fa2>] bus_remove_driver+0x57/0x75
>  [<c02227fd>] driver_unregister+0x8/0x13
>  [<c01ccdfd>] pci_unregister_driver+0xc/0x67
>  [<c0134133>] sys_delete_module+0x15c/0x19d
>  [<c0149fc0>] remove_vma+0x31/0x36
>  [<c014a946>] do_munmap+0x19b/0x1b4
>  [<c0104cca>] sysenter_past_esp+0x5f/0x85
>  [<c0300000>] packet_notifier+0xf3/0x157
>  =======================
> Code: ff c3 85 c0 74 08 83 c0 08 e9 83 6d f6 ff b8 ea ff ff ff c3 85 c0 74 08 
> 83 c0 08 e9 4c 51 f6 ff c3 57 89 c7 56 53 8b 70 44 31 db <83> be 94 00 00 00 
> 00 75 09 eb 17 89 f8 e8 d7 ff ff ff 89 da 83
> EIP: [<c0222af4>] class_device_remove_attrs+0xa/0x30 SS:ESP 0068:d93e7e1c
> 
> 
> Checking Google I see a similar oops was reported long ago: 
> http://lkml.org/lkml/2006/11/16/147 .
> 
> Any ideas/patches to test? Please CC me in your replies.

Thanks for the report.  Do you have a script or config which marks the
ohci1394 module to be unloaded before suspend?  This should not be
necessary since 2.6.21-rc1 anymore.  (Although I tested this only with
APM suspend to RAM and only with the sbp2 driver as IEEE 1394
application-layer software, and only with current 1394 drivers on top of
2.6.20-rcX instead of 2.6.21-rcX.  I heard that raw1394 survives
suspend/resume thanks to the ohci1394 updates already in 2.6.20.)

But back to your problem.  The older report which you pointed to was a
hickup caused by the ongoing conversion away from class_device.  Further
down that discussion, a 2.6.19-rcX-mmY patch was discovered to trigger
this:  http://lkml.org/lkml/2006/11/19/53
|  the winner is... gregkh-driver-network-device.patch
By "trigger" I mean that I don't know where the bug was, i.e. in the
then partial driver core conversion or in the ieee1394 nodemgr.

*However*, this time it's different --- you don't have eth1394 present.

I will boot 2.6.21-rc3 on a spare machine and see how it goes.

As a side note, the IEEE 1394 subsystem features quite a fat usage of
the driver core.  We have (in order of parent devices to child devices)
the host adapter's PCI device's device, the 1394 host device
(hpsb_host), the node entry devices, the unit directory devices.  And
all of them have respective class devices.  But really important outside
of the ieee1394 core are only the first and the last, i.e. PCI device
and unit directories.  Maybe we should redesign nodemgr to work without
host devices and node entry devices.

Side note to the side note:  The new alternative IEEE 1394 drivers which
are currently maturing in -mm (the 1394 stack nicknamed Juju), does
indeed create only unit directory devices if I'm not badly mistaken.
-- 
Stefan Richter
-=====-=-=== --== -===-
http://arcgraph.de/sr/
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