Comment 4 for bug 1403459

Same result with linux 3.18 from OBS Kernel:HEAD:

# uname -a
Linux opensuse 3.18.0-rc7-2.g088d59b-default #1 SMP Fri Dec 5 00:03:54 UTC 2014 (088d59b) x86_64 x86_64 x86_64 GNU/Linux
# dmesg
[ 150.252464] CPU2 has been hot-added
[ 150.253350] smpboot: Booting Node 0 Processor 2 APIC 0x2
[ 0.004000] kvm-clock: cpu 2, msr 2:403de081, secondary cpu clock
[ 150.268003] TSC synchronization [CPU#1 -> CPU#2]:
[ 150.268003] Measured 518729842258 cycles TSC warp between CPUs, turning off TSC clock.
[ 150.268003] tsc: Marking TSC unstable due to check_tsc_sync_source failed
[ 150.285117] KVM setup async PF for cpu 2
[ 150.285201] kvm-stealtime: cpu 2, msr 24008c280
[ 150.296118] kobject '(null)' (ffffe8ffffc8b5d8): tried to add an uninitialized object, something is seriously wrong.
[ 150.296197] CPU: 1 PID: 1386 Comm: systemd-udevd Not tainted 3.18.0-rc7-2.g088d59b-default #1
[ 150.296243] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014
[ 150.296285] 0000000000000000 0000000000000002 ffffffff81605f07 ffffe8ffffc8b5d8
[ 150.296332] ffffffff8132c7a0 ffff88023341d370 0000000000000020 ffff8800bb05bd58
[ 150.296382] ffff8800bb05bd08 000000000000a0a0 000000003f441940 0000000000000007
[ 150.296427] Call Trace:
[ 150.296479] [<ffffffff81005306>] dump_trace+0x86/0x330
[ 150.296541] [<ffffffff81005644>] show_stack_log_lvl+0x94/0x170
[ 150.296596] [<ffffffff81006d21>] show_stack+0x21/0x50
[ 150.296673] [<ffffffff81605f07>] dump_stack+0x41/0x51
[ 150.296721] [<ffffffff8132c7a0>] kobject_add+0xa0/0xb0
[ 150.296767] [<ffffffff8130aee1>] blk_mq_register_hctx+0x91/0xb0
[ 150.296809] [<ffffffff8130b82e>] blk_mq_sysfs_register+0x3e/0x60
[ 150.296857] [<ffffffff81309298>] blk_mq_queue_reinit_notify+0xf8/0x190
[ 150.296900] [<ffffffff8107cfdc>] notifier_call_chain+0x4c/0x70
[ 150.296947] [<ffffffff8105fd23>] cpu_notify+0x23/0x50
[ 150.296988] [<ffffffff81060037>] _cpu_up+0x157/0x170
[ 150.297033] [<ffffffff810600d9>] cpu_up+0x89/0xb0
[ 150.297079] [<ffffffff815fa5b5>] cpu_subsys_online+0x35/0x80
[ 150.297127] [<ffffffff814323cd>] device_online+0x5d/0xa0
[ 150.297185] [<ffffffff81432485>] online_store+0x75/0x80
[ 150.297238] [<ffffffff81236a5a>] kernfs_fop_write+0xda/0x150
[ 150.297309] [<ffffffff811c5532>] vfs_write+0xb2/0x1f0
[ 150.297367] [<ffffffff811c5f42>] SyS_write+0x42/0xb0
[ 150.297442] [<ffffffff8160c4ed>] system_call_fastpath+0x16/0x1b
[ 150.297493] [<00007f0132fb24e0>] 0x7f0132fb24e0
[ 150.297583] microcode: CPU2 sig=0x306c1, pf=0x1, revision=0x1
[ 150.297727] Will online and init hotplugged CPU: 2