Re: KVM Guest mmap.c bug

[Avi Kivity <avi@redhat.com>]

On 03/02/2010 10:25 PM, BRUNO CESAR RIBAS wrote:
> Hi,
>
> I run a bunch of virtual servers using KVM. And I a mmap.c bug on the guest
> machine. The virtual machines are "desktop servers" for Thin Clients.
>
> My host is running a 2.6.33 kernel and have 32GB of rami, opteron with
> amd-v.
>
> The guest is running 2.6.27.45 (tried 2.6.31.12, 2.6.32.9, 2.6.33), some
> guests are using 10GB, 4GB or 20GB of ram.
>
> My qemu-kvm version is 0.12.3
>
> All guests are using NFSROOT as the ROOT FS and virtio as the network
> driver.
>
> I run the guest with:
> kvm  -cpu kvm64 -smp 4 -vnc :101 -daemonize -name ${NOME} -localtime -m $RAM
> -net nic,macaddr=$VLAN0,model=virtio,vlan=0 -net tap,vlan=0,ifname=${NOME}0\
> -net nic,macaddr=$VLAN121,model=virtio,vlan=121 -net tap,vlan=121,ifname=${NOME}121\
> -net nic,macaddr=$VLAN112,model=virtio,vlan=112 -net tap,vlan=112,ifname=${NOME}112\
> -kernel /root/vmlinuz-2.6.27.45-amd64-aufs-guest \
> -append "root=/dev/nfs rw ip=dhcp nfsroot=$5 init=/sbin/boot.sh"
>
>
> I have a machine running an identical kernel (without virtio stuff) for a
> dedicated machine (as it does not have amd-v) and it stays up for days and
> even months. But when running a guest machine with qemu-kvm i get some bug
> message and lots of process in D state and i can't 'ps aux' or look inside
> /proc and /sys without losing my shell (it hangs).
>
>    

> In `console` I get the folowing message, repeated for different processor,
> different Pid and diferent  mmap.c line (line 486 appears to).
>
> ------------[ cut here ]------------
> kernel BUG at mm/mmap.c:869!
> invalid opcode: 0000 [1] SMP
> CPU 2
> Pid: 31334, comm: nautilus Not tainted 2.6.27.45-amd64-aufs-guest-00267
>   #2
> RIP: 0010:[<ffffffff8027b2e1>]  [<ffffffff8027b2e1>] find_mergeable_ano
> f1/0x200
> RSP: 0000:ffff8804d933fb38  EFLAGS: 00010283
> RAX: ffff8804cb44b9a8 RBX: ffff8804cb44b978 RCX: ffff8804fe6d3088
> RDX: 00000000f4803000 RSI: ffff8804fe6d3088 RDI: ffff88049fa56138
> RBP: ffff88049fa56138 R08: ffff8804d933e000 R09: 0000000000000000
> R10: 00000000ffffffff R11: 00000000ffffffff R12: 0000000000100073
> R13: 0000000000100073 R14: 00000000f4803000 R15: ffffffff806ce6c0
> FS:  0000000000000000(0000) GS:ffff88051cc7d440(0063) knlGS:00000000f41
> CS:  0010 DS: 002b ES: 002b CR0: 000000008005003b
> CR2: 00000000f4803000 CR3: 00000004a7d39000 CR4: 00000000000006a0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process nautilus (pid: 31334, threadinfo ffff8804d933e000, task ffff880
> )
> Stack:  ffffffff8052e62d 0000000000000000 0000000000000000 ffff88049fa5
>   ffff88051a5aac40 ffffffff80280382 ffff8804cb41b790 ffff880498919018
>   0000000000000000 ffff88049f8dad20 00003ffffffff000 ffffffff802770aa
> Call Trace:
>   [<ffffffff8052e62d>] ? _spin_lock_irq+0xd/0x10
>   [<ffffffff80280382>] ? anon_vma_prepare+0x52/0x100
>   [<ffffffff802770aa>] ? handle_mm_fault+0x65a/0x900
>   [<ffffffff802de6d8>] ? proc_alloc_inode+0x58/0x90
>   [<ffffffff8052e545>] ? __down_read+0x85/0xbc
>   [<ffffffff80223331>] ? do_page_fault+0x2a1/0xab0
>   [<ffffffff803d6899>] ? vsnprintf+0x4d9/0x750
>   [<ffffffff8029d7a1>] ? do_lookup+0x81/0x240
>   [<ffffffff8027265d>] ? zone_statistics+0x7d/0x80
>   [<ffffffff8052ea3a>] ? error_exit+0x0/0x70
>   [<ffffffff803d706d>] ? copy_user_generic_string+0x2d/0x40
>   [<ffffffff802e35ec>] ? proc_file_read+0x12c/0x2e0
>   [<ffffffff802e34c0>] ? proc_file_read+0x0/0x2e0
>   [<ffffffff802dec1a>] ? proc_reg_read+0x8a/0xe0
>   [<ffffffff80295995>] ? vfs_read+0xb5/0x160
>   [<ffffffff80295b2e>] ? sys_read+0x4e/0x90
>   [<ffffffff80227004>] ? ia32_sysret+0x0/0x5
>
>
> Code: 29 d0 48 c1 e8 0c 48 01 f8 48 3b 83 88 00 00 00 0f 85 5b fe ff ff
>   78 e9 c5 fe ff ff 0f 1f 00 31 f6 31 db e9 a9 fe ff ff<0f>  0b eb fe 66
>   1f 84 00 00 00 00 00 48 83 ec 08 48 8b
> RIP  [<ffffffff8027b2e1>] find_mergeable_anon_vma+0x1f1/0x200
>   RSP<ffff8804d933fb38>
> ---[ end trace e5ca25224cd7d1d4 ]---
>
>
> Does anyone has a sugestion? Where to look? What else should I trace?
>
>    

It looks unrelated to kvm, though of course random memory corruption 
cannot be ruled out.

Is npt enabled on the host (cat /sys/module/kvm_amd/parameters/npt)?

Andrea, any idea?

-- 
error compiling committee.c: too many arguments to function