Confirm on Ubuntu 9.10 under KVM virtualisation.

silenkov@v_mysql03:~$ uname -a 
Linux v_mysql06 2.6.31-14-generic #48-Ubuntu SMP Fri Oct 16 14:05:01 UTC 2009 x86_64 GNU/Linux

Kern.log output:

Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] BUG: soft lockup - CPU#2 stuck for 61s! [mysqld:17040]
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] Modules linked in: ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs xfs exportfs reiserfs iptable_filter ip_tables x_tables i2c_piix4 psmouse lp parport serio_raw virtio_balloon virtio_net virtio_blk floppy virtio_pci virtio_ring virtio
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] CPU 2:
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] Modules linked in: ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs xfs exportfs reiserfs iptable_filter ip_tables x_tables i2c_piix4 psmouse lp parport serio_raw virtio_balloon virtio_net virtio_blk floppy virtio_pci virtio_ring virtio
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] Pid: 17040, comm: mysqld Not tainted 2.6.31-14-generic #48-Ubuntu 
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] RIP: 0010:[<ffffffff81035257>]  [<ffffffff81035257>] kvm_mmu_op+0x47/0x70
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] RSP: 0018:ffff88007c10fc18  EFLAGS: 00000297
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] RAX: 0000000000000000 RBX: ffff88007c10fc48 RCX: 0000000001a3e5b0
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] RDX: 0000000000000000 RSI: 0000000000000020 RDI: ffff880001a3e5b0
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] RBP: ffffffff81012bae R08: 00000000ffffff77 R09: 0000000000000000
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88007c10fc48
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] R13: ffffffff81012bae R14: 0000000000000000 R15: 0000000000000002
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] FS:  00007fc401254910(0000) GS:ffff880001a30000(0000) knlGS:0000000000000000
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] CR2: 00007fc3e04351d8 CR3: 000000005acd1000 CR4: 00000000000006e0
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638] Call Trace:
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff8103524b>] ? kvm_mmu_op+0x3b/0x70
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810352b4>] ? kvm_leave_lazy_mmu+0x34/0x50
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810f5c07>] ? zap_pte_range+0x187/0x400
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810e5344>] ? release_pages+0x234/0x260
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810dba70>] ? T.768+0x3a0/0x440
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810f6040>] ? unmap_page_range+0x1c0/0x290
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810f6277>] ? unmap_vmas+0x167/0x2f0
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810f75e1>] ? zap_page_range+0xb1/0x120
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810f35e7>] ? madvise_vma+0x1a7/0x1f0
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff810f375d>] ? sys_madvise+0x12d/0x270
Mar  3 05:32:51 v_mysql03 kernel: [217826.790638]  [<ffffffff81012002>] ? system_call_fastpath+0x16/0x1b


root@v_mysql03:~# free
             total       used       free     shared    buffers     cached
Mem:       3041464     645500    2395964          0      59464     163000
-/+ buffers/cache:     423036    2618428
Swap:      4194296          0    4194296

Couldn't reproduce a bug. It appears randomly without interaction of server load. Memory and CPU's are ok.