abrt version: 2.0.1
architecture:   x86_64
cmdline:        ro root=UUID=ac977577-24ab-4b6a-af31-2af93d2ceb88 rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=fr-pc rhgb quiet
component:      kernel
kernel:         2.6.38.8-32.fc15.x86_64
kernel_tainted: 128
os_release:     Fedora release 15 (Lovelock)
package:        kernel
reason:         BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1087
reported_to:    kerneloops: URL=http://submit.kerneloops.org/submitoops.php
time:           Sun Jun 26 14:17:10 2011

backtrace:
:BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1087
:in_atomic(): 0, irqs_disabled(): 1, pid: 1545, name: umount
:Pid: 1545, comm: umount Not tainted 2.6.38.8-32.fc15.x86_64 #1
:Call Trace:
: [<ffffffff81047d33>] __might_sleep+0xeb/0xf0
: [<ffffffff81478dc3>] do_page_fault+0x1eb/0x37a
: [<ffffffffa01678bd>] ? map_extent_buffer+0x6e/0xa8 [btrfs]
: [<ffffffffa0167828>] ? map_private_extent_buffer+0xb1/0xd8 [btrfs]
: [<ffffffffa0132cbe>] ? comp_keys+0x2b/0x2d [btrfs]
: [<ffffffffa0167908>] ? unmap_extent_buffer+0x11/0x13 [btrfs]
: [<ffffffff814761d5>] page_fault+0x25/0x30
: [<ffffffff81211486>] ? elv_may_queue+0x10/0x1f
: [<ffffffffa0167412>] ? read_extent_buffer+0xc3/0xe3 [btrfs]
: [<ffffffff81215ba2>] get_request+0x33/0x262
: [<ffffffff8121676a>] get_request_wait+0x35/0x193
: [<ffffffff810b07a4>] ? __call_rcu+0x123/0x12c
: [<ffffffff81216907>] blk_get_request+0x3f/0x6e
: [<ffffffff812fc861>] scsi_execute+0x41/0x146
: [<ffffffff812fca02>] scsi_execute_req+0x9c/0xce
: [<ffffffff812f8a9c>] ioctl_internal_command.constprop.1+0x6b/0x163
: [<ffffffff812f8bed>] scsi_set_medium_removal+0x59/0x94
: [<ffffffff8130b225>] sr_lock_door+0x20/0x22
: [<ffffffff8132c475>] cdrom_release+0x195/0x205
: [<ffffffff810806d9>] ? smp_call_function_many+0x1bd/0x1dc
: [<ffffffff8104127e>] ? should_resched+0xe/0x2d
: [<ffffffff81474408>] ? _cond_resched+0xe/0x22
: [<ffffffff8130a1b9>] sr_block_release+0x30/0x4d
: [<ffffffff81149aa2>] __blkdev_put+0xc6/0x179
: [<ffffffff81149c59>] blkdev_put+0x104/0x10c
: [<ffffffff81122f69>] kill_block_super+0x65/0x6a
: [<ffffffff811231a5>] deactivate_locked_super+0x26/0x4b
: [<ffffffff81123d0e>] deactivate_super+0x37/0x3b
: [<ffffffff8113863c>] mntput_no_expire+0xcc/0xd1
: [<ffffffff81139073>] sys_umount+0x2ac/0x2da
: [<ffffffff81009bc2>] system_call_fastpath+0x16/0x1b

comment:
:I have a USB optical drive.
:
:This happens every time I unplug its USB cables.

event_log:
:2011-06-26-14:20:25> Submitting oops report to http://submit.kerneloops.org/submitoops.php
:2011-06-26-14:20:43  Kernel oops report was uploaded