Bug 1175261

Summary: kernel bug when hotplugging a CPU
Product: [Fedora] Fedora Reporter: Benjamin Drung <bdrung>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 21CC: gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda, mchehab
Target Milestone: ---   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: kernel-3.17.8-200.fc20 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-01-11 02:58:01 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Benjamin Drung 2014-12-17 11:40:48 UTC 
When I hot-plug a CPU to a Fedora 21 VM running on KVM, I get following kernel bug:

$ uname -a
Linux fedora 3.17.6-300.fc21.x86_64 #1 SMP Mon Dec 8 22:29:32 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
$ journalctl
Dez 17 10:40:21 fedora kernel: CPU1 has been hot-added
Dez 17 10:40:21 fedora kernel: SMP alternatives: switching to SMP code
Dez 17 10:40:21 fedora kernel: x86: Booting SMP configuration:
Dez 17 10:40:21 fedora kernel: smpboot: Booting Node 0 Processor 1 APIC 0x1
Dez 17 10:40:21 fedora kernel: kvm-clock: cpu 1, msr 0:3ffca041, secondary cpu clock
Dez 17 10:40:21 fedora kernel: kvm: enabling virtualization on CPU1
Dez 17 10:40:21 fedora kernel: KVM setup async PF for cpu 1
Dez 17 10:40:21 fedora kernel: kvm-stealtime: cpu 1, msr 3de2d100
Dez 17 10:40:21 fedora kernel: kobject '(null)' (ffff88003de3b4d8): tried to add an uninitialized object, something is seriously wrong.
Dez 17 10:40:21 fedora kernel: CPU: 1 PID: 1056 Comm: systemd-udevd Not tainted 3.17.6-300.fc21.x86_64 #1
Dez 17 10:40:21 fedora kernel: Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Dez 17 10:40:21 fedora kernel:  0000000000000000 00000000ffd31f20 ffff88003b593c68 ffffffff8173f8aa
Dez 17 10:40:21 fedora kernel:  ffff88003de3b4d8 ffff88003b593ce0 ffffffff813850e6 ffffffff00000020
Dez 17 10:40:21 fedora kernel:  ffff88003b593cf0 ffff88003b593c98 00000000ffd31f20 0000000000000002
Dez 17 10:40:21 fedora kernel: Call Trace:
Dez 17 10:40:21 fedora kernel:  [<ffffffff8173f8aa>] dump_stack+0x45/0x56
Dez 17 10:40:21 fedora kernel:  [<ffffffff813850e6>] kobject_add+0xc6/0xd0
Dez 17 10:40:21 fedora kernel:  [<ffffffff81383bd5>] ? ida_get_new_above+0x1f5/0x220
Dez 17 10:40:21 fedora kernel:  [<ffffffff81362376>] blk_mq_register_hctx+0xa6/0xc0
Dez 17 10:40:21 fedora kernel:  [<ffffffff81362cb1>] blk_mq_sysfs_register+0x41/0x60
Dez 17 10:40:21 fedora kernel:  [<ffffffff813606b2>] blk_mq_queue_reinit_notify+0x72/0xb0
Dez 17 10:40:21 fedora kernel:  [<ffffffff810b62dd>] notifier_call_chain+0x4d/0x70
Dez 17 10:40:21 fedora kernel:  [<ffffffff810b63ee>] __raw_notifier_call_chain+0xe/0x10
Dez 17 10:40:21 fedora kernel:  [<ffffffff81097363>] cpu_notify+0x23/0x50
Dez 17 10:40:21 fedora kernel:  [<ffffffff81097598>] _cpu_up+0x188/0x1a0
Dez 17 10:40:21 fedora kernel:  [<ffffffff8109763a>] cpu_up+0x8a/0xb0
Dez 17 10:40:21 fedora kernel:  [<ffffffff81738fa0>] cpu_subsys_online+0x40/0xa0
Dez 17 10:40:21 fedora kernel:  [<ffffffff814975b5>] device_online+0x65/0x90
Dez 17 10:40:21 fedora kernel:  [<ffffffff81497675>] online_store+0x95/0xa0
Dez 17 10:40:21 fedora kernel:  [<ffffffff81494708>] dev_attr_store+0x18/0x30
Dez 17 10:40:21 fedora kernel:  [<ffffffff812895fa>] sysfs_kf_write+0x3a/0x50
Dez 17 10:40:21 fedora kernel:  [<ffffffff812889de>] kernfs_fop_write+0xee/0x180
Dez 17 10:40:21 fedora kernel:  [<ffffffff8120c597>] vfs_write+0xb7/0x1f0
Dez 17 10:40:21 fedora kernel:  [<ffffffff81060e21>] ? trace_do_page_fault+0x41/0x100
Dez 17 10:40:21 fedora kernel:  [<ffffffff8120d1c5>] SyS_write+0x55/0xd0
Dez 17 10:40:21 fedora kernel:  [<ffffffff81746a69>] system_call_fastpath+0x16/0x1b
Dez 17 10:40:21 fedora kernel: microcode: CPU1: patch_level=0x01000065
Dez 17 10:40:21 fedora kernel: Will online and init hotplugged CPU: 1

I initially reported this bug in openSUSE and it was fixed in the Linus tree: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=06a41a9
Comment 1 Josh Boyer 2014-12-18 13:51:56 UTC 
Thanks for the report and the pointer to the patch.  I've updated Fedora git to have this and it will be in the next build of each release.
Comment 2 Fedora Update System 2015-01-09 13:10:02 UTC 
kernel-3.17.8-300.fc21 has been submitted as an update for Fedora 21.
https://admin.fedoraproject.org/updates/kernel-3.17.8-300.fc21
Comment 3 Fedora Update System 2015-01-09 13:10:54 UTC 
kernel-3.17.8-200.fc20 has been submitted as an update for Fedora 20.
https://admin.fedoraproject.org/updates/kernel-3.17.8-200.fc20
Comment 4 Fedora Update System 2015-01-10 03:00:19 UTC 
Package kernel-3.17.8-200.fc20:
* should fix your issue,
* was pushed to the Fedora 20 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing kernel-3.17.8-200.fc20'
as soon as you are able to, then reboot.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2015-0515/kernel-3.17.8-200.fc20
then log in and leave karma (feedback).
Comment 5 Fedora Update System 2015-01-11 02:58:01 UTC 
kernel-3.17.8-300.fc21 has been pushed to the Fedora 21 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 6 Fedora Update System 2015-01-13 00:05:38 UTC 
kernel-3.17.8-200.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.