Re: [2.6.26] kobject_add_internal failed for 2:0 with -EEXIST / unable to handle kernel NULL pointer dereference in sysfs_create_link

["Kay Sievers" <kay.sievers@vrfy.org>]

On Tue, Oct 28, 2008 at 16:11, Folkert van Heusden
<folkert@vanheusden.com> wrote:
> While running my http://vanheusden.com/pyk/ script (which randomly
> inserts and removes modules) I triggered the folllowing oops in a 2.6.26
> kernel on an IBM xSeries 260. This oops (in fact no oops at all) did not
> get triggered in a 2.6.18 kernel on that system.
>
> [   42.507375] FDC 0 is a National Semiconductor PC87306
> [   42.509057] kobject_add_internal failed for 2:0 with -EEXIST, don't try to register things with the same name in the same directory.
> [   42.509291] Pid: 5301, comm: modprobe Not tainted 2.6.26-1-amd64 #1
> [   42.509431]
> [   42.509433] Call Trace:
> [   42.509685]  [<ffffffff8031b031>] kobject_add_internal+0x13f/0x17e
> [   42.509823]  [<ffffffff8031b46e>] kobject_add+0x74/0x7c
> [   42.509969]  [<ffffffff802e2470>] sysfs_addrm_finish+0x19/0x1ea
> [   42.510141]  [<ffffffff802e21b4>] sysfs_find_dirent+0x1b/0x2f
> [   42.510331]  [<ffffffff802e2741>] create_dir+0x5a/0x87
> [   42.510466]  [<ffffffff8031ae88>] kobject_get+0x12/0x17
> [   42.510614]  [<ffffffff80382771>] get_device+0x17/0x20
> [   42.510754]  [<ffffffff80382d81>] device_add+0x9b/0x53f
> [   42.510915]  [<ffffffff8031acf2>] kobject_init+0x41/0x69
> [   42.511374]  [<ffffffff803832d1>] device_create_vargs+0x9a/0xc6
> [   42.511519]  [<ffffffff8027d23b>] bdi_register+0x57/0xb4

Looks like bdi sees two devices with the same devnum, or didn't
cleanup an old entry.

What does: ls -l "/sys/class/bdi/" print?

How many floppies (or emulated floppies) does this system have?

Kay