>>
>> I tried to reproduce such a problem, and I found L2 (Linux) hangs in
>> SeaBIOS, after line "iPXE (http://ipxe.org) ...". It happens with or
>> w/o VMCS shadowing (and even without my virtual EPT patches). I didn't
>> realize this problem until I updated the L1 kernel to the latest (e.g.
>> 3.9.0) from 3.7.0. L0 uses the kvm.git, next branch. It's possible
>> that the L1 kernel exposed a bug with the nested virtualization, as we
>> saw such cases before.
>>
> This is probably fixed by 8d76c49e9ffeee839bc0b7a3278a23f99101263e. Try
> it please.
I don't see the above SeaBIOS hang, however I'm able to consistently
reproduce this stack trace when booting L1 guest:
============
....
[ 2.516894] VFS: Cannot open root device "mapper/fedora-root" or
unknown-block(0,0): error -6
[ 2.527636] Please append a correct "root=" boot option; here are
the available partitions:
[ 2.538792] Kernel panic - not syncing: VFS: Unable to mount root
fs on unknown-block(0,0)
[ 2.539716] Pid: 1, comm: swapper/0 Not tainted 3.8.11-200.fc18.x86_64 #1
[ 2.539716] Call Trace:
[ 2.539716] [<ffffffff81649c19>] panic+0xc1/0x1d0
[ 2.539716] [<ffffffff81d010e0>] mount_block_root+0x1fa/0x2ac
[ 2.539716] [<ffffffff81d011e9>] mount_root+0x57/0x5b
[ 2.539716] [<ffffffff81d0132a>] prepare_namespace+0x13d/0x176
[ 2.539716] [<ffffffff81d00e1c>] kernel_init_freeable+0x1cf/0x1da
[ 2.539716] [<ffffffff81d00610>] ? do_early_param+0x8c/0x8c
[ 2.539716] [<ffffffff81637ca0>] ? rest_init+0x80/0x80
[ 2.539716] [<ffffffff81637cae>] kernel_init+0xe/0xf0
[ 2.539716] [<ffffffff8165bd6c>] ret_from_fork+0x7c/0xb0
[ 2.539716] [<ffffffff81637ca0>] ? rest_init+0x80/0x80
[ 2.539716] Uhhuh. NMI received for unknown reason 30 on CPU 1.
[ 2.539716] Do you have a strange power saving mode enabled?
[ 2.539716] Dazed and confused, but trying to continue
[ 2.539716] Uhhuh. NMI received for unknown reason 20 on CPU 1.
============
Howver, L1 boots just fine.
When I try to boot L2, it throws this different stack trace.
============
[176092.303585] lock(&dev->device_lock);
[176092.307947]
[176092.307947] *** DEADLOCK ***
[176092.307947]
[176092.314943] 2 locks held by systemd/1:
[176092.319283] #0: (misc_mtx){+.+.+.}, at: [<ffffffff814534b8>]
misc_open+0x28/0x1d0
[176092.328104] #1: (&wdd->lock){+.+...}, at: [<ffffffff81557f22>]
watchdog_start+0x22/0x80
[176092.337532]
[176092.337532] stack backtrace:
[176092.342661] CPU: 1 PID: 1 Comm: systemd Not tainted
3.10.0-0.rc0.git23.1.fc20.x86_64 #1
[176092.351823] Hardware name: Intel Corporation Shark Bay Client
platform/Flathead Creek Crb, BIOS HSWLPTU1.86C.0109.R03.1301282055
01/28/2013
[176092.366101] ffffffff8257d070 ffff880241b1b9c0 ffffffff81719128
ffff880241b1ba00
[176092.374617] ffffffff81714d75 ffff880241b1ba50 ffff880241b80960
ffff880241b80000
[176092.383130] 0000000000000002 0000000000000002 ffff880241b80960
ffff880241b1bac0
[176092.391647] Call Trace:
[176092.394514] [<ffffffff81719128>] dump_stack+0x19/0x1b
2m OK ] Re[176092.400430] [<ffffffff81714d75>] print_circular_bug+0x201/0x210
[176092.408898] [<ffffffff810db094>] __lock_acquire+0x17c4/0x1b30
ached target Shu[176092.415602] [<ffffffff81720d7c>] ?
_raw_spin_unlock_irq+0x2c/0x50
[176092.424276] [<ffffffff810dbbf2>] lock_acquire+0xa2/0x1f0
tdown.
[176092.430489] [<ffffffff8149028d>] ? mei_wd_ops_start+0x2d/0xf0
[176092.438070] [<ffffffff8171d590>] mutex_lock_nested+0x80/0x400
[176092.444772] [<ffffffff8149028d>] ? mei_wd_ops_start+0x2d/0xf0
[176092.451471] [<ffffffff8149028d>] ? mei_wd_ops_start+0x2d/0xf0
[176092.458172] [<ffffffff81557f22>] ? watchdog_start+0x22/0x80
[176092.464678] [<ffffffff81557f22>] ? watchdog_start+0x22/0x80
[176092.471182] [<ffffffff8149028d>] mei_wd_ops_start+0x2d/0xf0
[176092.477687] [<ffffffff81557f5d>] watchdog_start+0x5d/0x80
[176092.483994] [<ffffffff81558168>] watchdog_open+0x88/0xf0
[176092.490214] [<ffffffff81453547>] misc_open+0xb7/0x1d0
[176092.496128] [<ffffffff811e15d2>] chrdev_open+0x92/0x1d0
[176092.502240] [<ffffffff811da57b>] do_dentry_open+0x24b/0x300
[176092.508745] [<ffffffff812e8e7c>] ? security_inode_permission+0x1c/0x30
[176092.516330] [<ffffffff811e1540>] ? cdev_put+0x30/0x30
[176092.522243] [<ffffffff811da670>] finish_open+0x40/0x50
[176092.528256] [<ffffffff811ec139>] do_last+0x4d9/0xe40
[176092.534071] [<ffffffff811ecb53>] path_openat+0xb3/0x530
[176092.540193] [<ffffffff810acc1f>] ? local_clock+0x5f/0x70
[176092.546403] [<ffffffff8101fcf5>] ? native_sched_clock+0x15/0x80
[176092.553301] [<ffffffff810d5d9d>] ? trace_hardirqs_off+0xd/0x10
[176092.560099] [<ffffffff811ed658>] do_filp_open+0x38/0x80
[176092.566211] [<ffffffff81720c77>] ? _raw_spin_unlock+0x27/0x40
[176092.572913] [<ffffffff811fc39f>] ? __alloc_fd+0xaf/0x200
[176092.579123] [<ffffffff811db9a9>] do_sys_open+0xe9/0x1c0
[176092.585235] [<ffffffff811dba9e>] SyS_open+0x1e/0x20
[176092.590953] [<ffffffff8172a999>] system_call_fastpath+0x16/0x1b
Sending SIGTERM to remaining processes...
[176092.622745] systemd-journald[338]: Received SIGTERM
Sending SIGKILL to remaining processes...
Hardware watchdog 'INTCAMT', version 0
Unmounting file systems.
Unmounting /sys/kernel/config.
Unmounting /dev/mqueue.
Unmounting /dev/hugepages.
Unmounting /sys/kernel/debug.
[176094.363845] EXT4-fs (dm-1): re-mounted. Opts: (null)
[176094.548631] EXT4-fs (dm-1): re-mounted. Opts: (null)
[176094.554450] EXT4-fs (dm-1): re-mounted. Opts: (null)
All filesystems unmounted.
Deactivating swaps.
All swaps deactivated.
Detaching loop devices.
All loop devices detached.
Detaching DM devices.
Detaching DM 253:2.
Detaching DM 253:0.
Not all DM devices detached, 1 left.
Detaching DM devices.
Not all DM devices detached, 1 left.
Cannot finalize remaining file systems and devices, giving up.
Storage is finalized.
Successfully changed into root pivot.
Returning to initrd...
[176094.675812] dracut Warning: Killing all remaining processes
============
L1 Kernel: 3.10.0-0.rc0.git26.1.fc20.x86_64
L2 Kernel: 3.10.0-0.rc0.git26.1.fc20.x86_64
How I re-produced this, I noted it in my previous emails to this thread.
Am I doing anything plain incorrect ?
Thanks in advance.
/kashyap
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