3.12.1 Virt dev invalid for slot_id 0x1

I started seeing the following on my Samsung Series on 3.12.1

Is this bad? Looks like the following WARN_ON is firing:

drivers/usb/host/xhci.c:

if (WARN_ON(!virt_dev)) {
/*
* In plug/unplug torture test with an NEC controller,
* a zero-dereference was observed once due to virt_dev
= 0.
* Print useful debug rather than crash if it is
observed again!

                 */
                xhci_warn(xhci, "Virt dev invalid for slot_id 0x%x!\n",
                        udev->slot_id);
                return -EINVAL;
        }

[  565.276187] ------------[ cut here ]------------
[  565.276198] WARNING: CPU: 2 PID: 2228 at drivers/usb/host/xhci.c:3748 xhci_address_device+0x57b/0x630()
[  565.276262] Modules linked in: parport_pc ppdev arc4 iwldvm rfcomm bnep mac80211 i915 ext2 joydev x86_pkg_temp_thermal coretemp kvm_intel kvm iwlwifi uvcvideo videobuf2_vmalloc cfg80211 videobuf2_memops snd_hda_codec_hdmi videobuf2_core videodev drm_kms_helper snd_hda_codec_realtek ghash_clmulni_intel aesni_intel drm snd_hda_intel aes_x86_64 btusb media ablk_helper snd_hda_codec cryptd bluetooth lrw gf128mul glue_helper hid_generic samsung_laptop usbhid tpm_infineon hid snd_hwdep snd_pcm psmouse snd_page_alloc snd_timer microcode i2c_algo_bit lpc_ich serio_raw lp parport video wmi tpm_tis mac_hid r8169 mii
[  565.276267] CPU: 2 PID: 2228 Comm: kworker/u16:39 Not tainted 3.12.1+ #11
[  565.276269] Hardware name: SAMSUNG ELECTRONICS CO., LTD. 900X3C/900X3D/900X4C/900X4D/SAMSUNG_NP1234567890, BIOS P03AAC 07/12/2012
[  565.276278] Workqueue: events_unbound async_run_entry_fn
[  565.276285]  0000000000000009 ffff88002fb0fb00 ffffffff816bf0c1 0000000000000000
[  565.276289]  ffff88002fb0fb38 ffffffff8104d5fd ffff88040cc7e000 0000000000000000
[  565.276293]  ffff8803f0195800 0000000000000002 0000000000000000 ffff88002fb0fb48
[  565.276294] Call Trace:
[  565.276307]  [<ffffffff816bf0c1>] dump_stack+0x45/0x56
[  565.276314]  [<ffffffff8104d5fd>] warn_slowpath_common+0x7d/0xa0
[  565.276318]  [<ffffffff8104d6da>] warn_slowpath_null+0x1a/0x20
[  565.276324]  [<ffffffff8150a43b>] xhci_address_device+0x57b/0x630
[  565.276330]  [<ffffffff814d49d4>] hub_port_init+0x1f4/0xa40
[  565.276335]  [<ffffffff814d5336>] usb_reset_and_verify_device+0x116/0x730
[  565.276340]  [<ffffffff814d2ced>] ? hub_port_status+0xdd/0x120
[  565.276345]  [<ffffffff814d7bd0>] usb_port_resume+0x2f0/0x5c0
[  565.276352]  [<ffffffff814eb535>] generic_resume+0x15/0x30
[  565.276358]  [<ffffffff814e26e7>] usb_resume_both+0x107/0x150
[  565.276366]  [<ffffffff814d1e30>] ? usb_for_each_dev+0x30/0x30
[  565.276372]  [<ffffffff814e325f>] usb_resume+0x1f/0xd0
[  565.276377]  [<ffffffff814d1e30>] ? usb_for_each_dev+0x30/0x30
[  565.276383]  [<ffffffff814d1e43>] usb_dev_restore+0x13/0x20
[  565.276392]  [<ffffffff8143c179>] dpm_run_callback+0x49/0xa0
[  565.276398]  [<ffffffff8143c2d6>] device_resume+0xc6/0x1f0
[  565.276404]  [<ffffffff8143c41d>] async_resume+0x1d/0x50
[  565.276409]  [<ffffffff810766c7>] async_run_entry_fn+0x37/0x130
[  565.276418]  [<ffffffff81068357>] process_one_work+0x177/0x410
[  565.276424]  [<ffffffff81068f91>] worker_thread+0x121/0x3a0
[  565.276431]  [<ffffffff81068e70>] ? manage_workers.isra.25+0x2b0/0x2b0
[  565.276436]  [<ffffffff8106f730>] kthread+0xc0/0xd0
[  565.276442]  [<ffffffff8106f670>] ? kthread_create_on_node+0x120/0x120
[  565.276448]  [<ffffffff816ced2c>] ret_from_fork+0x7c/0xb0
[  565.276453]  [<ffffffff8106f670>] ? kthread_create_on_node+0x120/0x120
[  565.276456] ---[ end trace 115d14352276d432 ]---
[  565.276460] xhci_hcd 0000:03:00.0: Virt dev invalid for slot_id 0x1!
[  565.478224] ------------[ cut here ]------------

Shuah Khan
Senior Linux Kernel Developer - Open Source Group
Samsung Research America(Silicon Valley)
[email protected] | (970) 672-0658

I suggest sending this to the linux-usb@vger mailing list and cc: the xhci author/maintainer so they are aware of this.

thanks,

greg k-h