Hi Andrej, * Andrej Podzimek<andrej@xxxxxxxxxxxx> [2011-04-28 01:22:02 +0200]:Hello, after a recent kernel update on Arch Linux (2.6.38.4), I can see the following problem in dmesg: ------------[ cut here ]------------ WARNING: at lib/kobject.c:595 kobject_put+0x40/0x50() Hardware name: To Be Filled By O.E.M. kobject: '(null)' (ffff88023f60d5a0): is not initialized, yet kobject_put() is being called. Modules linked in: btusb(+) bluetooth rfkill usbhid hid button i2c_i801 i2c_core r8169 mii iTCO_wdt iTCO_vendor_support psmouse sg serio_raw evdev pcspkr ip_tables ip6_tables x_tables tpm_tis tpm tpm_bios w83627ehf hwmon_vid coretemp ext4 mbcache jbd2 crc16 dm_mod usb_storage raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx md_mod uhci_hcd xhci_hcd ehci_hcd usbcore sd_mod crc_t10dif ahci libahci libata scsi_mod cpufreq_ondemand acpi_cpufreq freq_table processor mperf i7core_edac edac_core Pid: 1820, comm: modprobe Not tainted 2.6.38-ARCH #1 Call Trace: [<ffffffff8103a86b>] ? warn_slowpath_common+0x7b/0xc0 [<ffffffff8103a965>] ? warn_slowpath_fmt+0x45/0x50 [<ffffffff81248d3f>] ? skb_dequeue+0x5f/0x80 [<ffffffff8116b6f0>] ? kobject_put+0x40/0x50 [<ffffffffa025f85c>] ? btusb_probe+0x57c/0x5e0 [btusb] [<ffffffffa00b85d5>] ? usb_probe_interface+0xe5/0x1e0 [usbcore] [<ffffffff81215aaf>] ? driver_probe_device+0x6f/0x190 [<ffffffff81215c63>] ? __driver_attach+0x93/0xa0 [<ffffffff81215bd0>] ? __driver_attach+0x0/0xa0 [<ffffffff81214b23>] ? bus_for_each_dev+0x53/0x80 [<ffffffff812153f8>] ? bus_add_driver+0x188/0x260 [<ffffffff81215e3a>] ? driver_register+0x6a/0x130 [<ffffffffa00b748a>] ? usb_register_driver+0x8a/0x180 [usbcore] [<ffffffffa011c000>] ? btusb_init+0x0/0x1000 [btusb] [<ffffffff810001dc>] ? do_one_initcall+0x3c/0x170 [<ffffffff8106db3a>] ? sys_init_module+0xda/0x230 [<ffffffff8100243b>] ? system_call_fastpath+0x16/0x1b ---[ end trace 9c4648061ddb0b67 ]--- Presumably, Bluetooth does not seem to work at all (i.e., hciconfig -a does not output anything). The output from lsusb -v relevant to the specific device is attached. The device worked 100% flawlessly with 2.6.38.3. I had an a2dp headset and a mouse paired with it, both of which worked perfectly fine in parallel.The only Bluetooth change in 2.6.38.4 is: https://lkml.org/lkml/2011/4/19/406 However I don't think this patch is causing this issue. Do you care to patch -R it and test? If the problem is somewhere else we have to go with a bisect, there are only 70 patches, so it shouldn't take to long. Greg, any idea on that? Are there similar reports of warnings for 2.6.38.4?
Hello, I'm sorry for this false positive. It was just a typical PEBKAC. The machine runs a WiFi access point and requires ath9k from compat-wireless (since the mainline ath9k can do no better than 2 Mb/s in AP mode). I installed compat-wireless as usual, but forgot to run scripts/driver-select. Consequently, all drivers (including Bluetooth, namely btusb) got replaced. So the backtrace was caused by using btusb from compat-wireless (April 26 2011) with kernel 2.6.38.4. The problem does *not* occur in a standard vanilla kernel. Andrej
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