Re: PROBLEM: HIDRAW: /dev/hidraw* device does not get removed when unplugged

[Alan Ott <alan@xxxxxxxxxxx>]

On 08/11/2010 11:28 AM, Alan Ott wrote:
> On 08/11/2010 11:21 AM, Jiri Kosina wrote:
> > On Wed, 11 Aug 2010, Alan Ott wrote:
> >
> > > Hello,
> > >
> > > I'm having a bit of trouble with hidraw (with a USB device) and device
> > > removal. When I remove a device and re-attach it, the original 
> > > device does not
> > > get removed, and another node is added to /dev.
> > >
> > > At boot:
> > >      no /dev/hidraw devices exist
> > >
> > > attach a device:
> > >      /dev/hidraw0 exists
> > >
> > > detach the device:
> > >      /dev/hidraw0 remains
> > >
> > > re-attach the device:
> > >      /dev/hidraw0 exists (defunct)
> > >      /dev/hidraw1 exists
> > >
> > > This is with 2.6.35+ from git, revision 3d30701b58970425e1d, updated 
> > > about 30
> > > minutes ago.
> > >
> > > Aug 11 11:04:15 ato kernel: [  109.554287] ------------[ cut here
> > > ]------------
> > > Aug 11 11:04:15 ato kernel: [  109.554300] WARNING: at 
> > > lib/kobject.c:595
> > > kobject_put+0x50/0x60()
> > > Aug 11 11:04:15 ato kernel: [  109.554306] Hardware name: 
> > > GA-MA770T-UD3P
> > > Aug 11 11:04:15 ato kernel: [  109.554311] kobject: '(null)'
> > > (ffff880244a49898): is not initialized, yet kobject_put() is being 
> > > called.
> > > Aug 11 11:04:15 ato kernel: [  109.554317] Modules linked in: usbhid 
> > > hid
> > > binfmt_misc fbcon tileblit font bitblit softcursor snd_hda_codec_nvhdmi
> > > nouveau snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep
> > > snd_pcm_oss ttm drm_kms_helper snd_mixer_oss snd_pcm drm snd_seq_dummy
> > > snd_seq_oss snd_seq_midi snd_rawmidi ppdev parport_pc 
> > > snd_seq_midi_event
> > > snd_seq psmouse lp snd_timer parport i2c_algo_bit edac_core video 
> > > edac_mce_amd
> > > i2c_piix4 snd_seq_device serio_raw snd soundcore snd_page_alloc output
> > > ohci1394 floppy pata_atiixp ieee1394 ahci libahci r8169 mii
> > > Aug 11 11:04:15 ato kernel: [  109.554399] Pid: 29, comm: khubd Not 
> > > tainted
> > > 2.6.35+ #19
> > > Aug 11 11:04:15 ato kernel: [  109.554404] Call Trace:
> > > Aug 11 11:04:15 ato kernel: [  109.554416]  [<ffffffff8105de1f>]
> > > warn_slowpath_common+0x7f/0xc0
> > > Aug 11 11:04:15 ato kernel: [  109.554425]  [<ffffffff8105df16>]
> > > warn_slowpath_fmt+0x46/0x50
> > > Aug 11 11:04:15 ato kernel: [  109.554434]  [<ffffffff812a47c0>]
> > > kobject_put+0x50/0x60
> > > Aug 11 11:04:15 ato kernel: [  109.554442]  [<ffffffff8135c6b7>]
> > > put_device+0x17/0x20
> > > Aug 11 11:04:15 ato kernel: [  109.554455]  [<ffffffffa0238998>]
> > > hid_destroy_device+0x48/0x60 [hid]
> > > Aug 11 11:04:15 ato kernel: [  109.554466]  [<ffffffffa00f2aeb>]
> > > usbhid_disconnect+0x2b/0x50 [usbhid]
> > > Aug 11 11:04:15 ato kernel: [  109.554477]  [<ffffffff813d620a>]
> > > usb_unbind_interface+0x5a/0x1a0
> > > Aug 11 11:04:15 ato kernel: [  109.554487]  [<ffffffff81360645>]
> > > __device_release_driver+0x75/0xe0
> > > Aug 11 11:04:15 ato kernel: [  109.554495]  [<ffffffff813607ad>]
> > > device_release_driver+0x2d/0x40
> > > Aug 11 11:04:15 ato kernel: [  109.554503]  [<ffffffff8135f79e>]
> > > bus_remove_device+0xae/0xf0
> > > Aug 11 11:04:15 ato kernel: [  109.554510]  [<ffffffff8135d437>]
> > > device_del+0x127/0x1d0
> > > Aug 11 11:04:15 ato kernel: [  109.554519]  [<ffffffff813d2b88>]
> > > usb_disable_device+0xa8/0x130
> > > Aug 11 11:04:15 ato kernel: [  109.554527]  [<ffffffff813cbe65>]
> > > usb_disconnect+0x95/0x130
> > > Aug 11 11:04:15 ato kernel: [  109.554535]  [<ffffffff813cd51d>]
> > > hub_thread+0x48d/0x1210
> > > Aug 11 11:04:15 ato kernel: [  109.554544]  [<ffffffff8105771b>] ?
> > > dequeue_task_fair+0x8b/0x90
> > > Aug 11 11:04:15 ato kernel: [  109.554555]  [<ffffffff8107e490>] ?
> > > autoremove_wake_function+0x0/0x40
> > > Aug 11 11:04:15 ato kernel: [  109.554563]  [<ffffffff813cd090>] ?
> > > hub_thread+0x0/0x1210
> > > Aug 11 11:04:15 ato kernel: [  109.554571]  [<ffffffff8107df36>]
> > > kthread+0x96/0xa0
> > > Aug 11 11:04:15 ato kernel: [  109.554580]  [<ffffffff8100be64>]
> > > kernel_thread_helper+0x4/0x10
> > > Aug 11 11:04:15 ato kernel: [  109.554588]  [<ffffffff8107dea0>] ?
> > > kthread+0x0/0xa0
> > > Aug 11 11:04:15 ato kernel: [  109.554595]  [<ffffffff8100be60>] ?
> > > kernel_thread_helper+0x0/0x10
> > > Aug 11 11:04:15 ato kernel: [  109.554601] ---[ end trace 
> > > 212263bbb326ec69
> > > ]---
> > > Aug 11 11:04:21 ato kernel: [  116.450553] usb 1-5.4: new full speed 
> > > USB
> > > device using ehci_hcd and address 7
> > > Aug 11 11:04:22 ato kernel: [  116.576230] generic-usb 
> > > 0003:04D8:003F.0002:
> > > hiddev0,hidraw1: USB HID v1.11 Device [Microchip Technology Inc. 
> > > Simple HID
> > > Device Demo] on usb-0000:00:12.2-5.4/input0
> > > Aug 11 11:04:23 ato kernel: [  117.746427] usb 1-5.4: USB 
> > > disconnect, address
> > > 7
> > > Aug 11 11:04:23 ato kernel: [  117.746500] ------------[ cut here
> > > ]------------
> > >
> > >
> > > lan@ato:~/work/linux-2.6$ scripts/ver_linux
> > > If some fields are empty or look unusual you may have an old version.
> > > Compare to the current minimal requirements in Documentation/Changes.
> > >
> > > Linux ato 2.6.35+ #19 SMP Wed Aug 11 10:53:49 EDT 2010 x86_64 GNU/Linux
> > >
> > > Gnu C                  4.4.3
> > > Gnu make               3.81
> > > binutils               2.20.1
> > > util-linux             2.17.2
> > > mount                  support
> > > module-init-tools      3.11.1
> > > e2fsprogs              1.41.11
> > > pcmciautils            014
> > > Linux C Library        2.11.1
> > > Dynamic linker (ldd)   2.11.1
> > > Procps                 3.2.8
> > > Net-tools              1.60
> > > Kbd                    1.15
> > > Sh-utils               7.4
> > > wireless-tools         30
> > > Modules Loaded         usbhid hid binfmt_misc fbcon tileblit font 
> > > bitblit
> > > softcursor snd_hda_codec_nvhdmi nouveau snd_hda_codec_realtek 
> > > snd_hda_intel
> > > snd_hda_codec snd_hwdep snd_pcm_oss ttm drm_kms_helper snd_mixer_oss 
> > > snd_pcm
> > > drm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi ppdev parport_pc
> > > snd_seq_midi_event snd_seq psmouse lp snd_timer parport i2c_algo_bit 
> > > edac_core
> > > video edac_mce_amd i2c_piix4 snd_seq_device serio_raw snd soundcore
> > > snd_page_alloc output ohci1394 floppy pata_atiixp ieee1394 ahci 
> > > libahci r8169
> > > mii
> > This looks very similar to http://lkml.org/lkml/2010/8/10/373
> >
> > I have not yet root-caused this, but I am not aware of any recent 
> > changes
> > in usb-hid that might be causing that, so I suspect some change in USB
> > core. But will have to investigate.
>
> I just tried it with a Bluetooth HID keyboard and it works as 
> expected. I'd suspect it to not be a HID problem.

I think the warning and the non-removal of the /dev/hidraw* node are 
unrelated.

I spent some time looking into the non-removal of the /dev/hidraw* node. 
The hid_disconnect() function takes care of removing the node, and it's 
not getting called. hid_disconnect() is called by hid_hw_stop() (hid.h), 
which is called by hid_device_remove() (hid-core.c) which _should_ be 
getting called by the driver subsystem. It looks like this is not 
happening for whatever reason.

I wasn't able to get anything conclusive beyond this (yet).

Alan.


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