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

Folkert van Heusden
2008-10-29T09:41:05Z

> > 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?

The following:
folkert@debiantesthw:~$ ls -l /sys/class/bdi/
total 0
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:0
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:1
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:10
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:11
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:12
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:13
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:14
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:15
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:2
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:3
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:4
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:5
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:6
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:7
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:8
drwxr-xr-x 3 root root 0 2008-10-28 18:32 1:9
drwxr-xr-x 3 root root 0 2008-10-28 18:32 2:0
drwxr-xr-x 3 root root 0 2008-10-28 18:32 2:1
drwxr-xr-x 3 root root 0 2008-10-28 18:32 254:0
drwxr-xr-x 3 root root 0 2008-10-28 18:32 254:1
drwxr-xr-x 3 root root 0 2008-10-28 18:32 254:2
drwxr-xr-x 3 root root 0 2008-10-28 18:32 254:3
drwxr-xr-x 3 root root 0 2008-10-28 18:32 254:4
drwxr-xr-x 3 root root 0 2008-10-28 18:32 254:5
drwxr-xr-x 3 root root 0 2008-10-28 18:32 3:0
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:0
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:1
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:2
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:3
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:4
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:5
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:6
drwxr-xr-x 3 root root 0 2008-10-29 11:39 7:7
drwxr-xr-x 3 root root 0 2008-10-28 18:32 8:0
drwxr-xr-x 3 root root 0 2008-10-28 18:32 default

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

1 physical.

Folkert van Heusden

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