Bug 768481

Summary:	Kernel panic - not syncing: VFS: Unable to mount root fs
Product:	[Fedora] Fedora	Reporter:	Tom <thomasbelvin>
Component:	kernel	Assignee:	Kernel Maintainer List <kernel-maint>
Status:	CLOSED DUPLICATE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	urgent
Version:	rawhide	CC:	dallan, gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-12-18 15:35:28 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Tom 2011-12-16 19:00:04 UTC

Description of problem:
Kernel panic at boot.

Version-Release number of selected component (if applicable):
3.2.0-0.rc5.git3.1.fc17.x86_64

How reproducible:
Everytime

Steps to Reproduce:
1.
2.
3.
  
Actual results:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block (0,0)
Pid:1, comm: swapper/0 Not tainted 3.2.0-0.rc5.git3.1.fc17.x86_64 #1
Call Trace:
[<ffffffff8166fcf6>] panic+0xa0/0x1bb
[<ffffffff81f6402c>] mount_block_root+0x1d1/0x283
[<ffffffff81002930>] ? name_to_dev_t+0x770/0xe40
[<ffffffff81f64131>] mount_root+0x53/0x57
[<ffffffff81f64272>] prepare_namespace+0x13d/0x176
[<ffffffff81f63d97>] kernel_init+0x159/0x15e
[<ffffffff81688604>] kernel_thread_helper+0x4/0x10
[<ffffffff8167df34>] ? retint_restore_args+0x13/0x13
[<ffffffff81f63c3e>] ? start_kernel+0x3f9/0x3f9
[<ffffffff81688600>] ? gs_change+0x13/0x13

Expected results:


Additional info:

Comment 1 Josh Boyer 2011-12-16 19:25:01 UTC

This is very likely caused by the kernel not having an initramfs passed to it.  Is there a corresponding initramfs in /boot for this kernel, and is it included in whichever grub configuration file your machine is using?

Do you have anything in /var/log/messages about depmod, new-kernel-pkg, or dracut segfaulting or any out-of-memory errors?

Comment 2 Tom 2011-12-17 01:44:45 UTC

I don't have initramfs for git3 kernel.

Comment 3 Dave Allan 2011-12-17 23:42:45 UTC

This panic is 100% reproducible for me on KVM VMs, exact same backtrace; I've installed one VM directly from the rawhide repo with the F16 installer and upgraded two other VMs.  All 3 panic'd on reboot.  I am happy to provide access to a VM exhibiting the problem, or anything else I can do to help troubleshoot it, as it's blocking me from verifying a libvirt bug.

Comment 4 Tom 2011-12-18 03:38:14 UTC

I took the dracut suggestion, and downgraded to previous dracut-013-100.git20111021.fc17, then reinstalled kernel. I now have initramfs and boots.

Comment 5 Josh Boyer 2011-12-18 15:35:28 UTC

Pretty sure this is this issue:

http://lists.fedoraproject.org/pipermail/devel/2011-December/160571.html

*** This bug has been marked as a duplicate of bug 768645 ***

Comment 6 Dave Allan 2011-12-19 21:23:06 UTC

Yep, that was it, thanks.  The steps in:

https://bugzilla.redhat.com/show_bug.cgi?id=768645#c1

got my systems booting again.