Restarted the same test with the default I/O scheduler and after a few hours, got the same crash again:

Jul 19 16:58:20 lantea kernel: [14707.004394] general protection fault: 0000 [#1] SMP 
Jul 19 16:58:20 lantea kernel: [14707.008026] 
Jul 19 16:58:20 lantea kernel: [14707.008026] Pid: 20505, comm: dbus-daemon Not tainted 3.5.0-5-generic #5-Ubuntu    /945GSE
Jul 19 16:58:20 lantea kernel: [14707.008026] EIP: 0060:[<c154d2fb>] EFLAGS: 00010286 CPU: 0
Jul 19 16:58:20 lantea kernel: [14707.008026] EIP is at unix_stream_recvmsg+0x4eb/0x680
Jul 19 16:58:20 lantea kernel: [14707.008026] EAX: 00000000 EBX: f28cc180 ECX: f18f1d40 EDX: ffffffff
Jul 19 16:58:20 lantea kernel: [14707.008026] ESI: 00000000 EDI: edd6c240 EBP: f18f1d68 ESP: f18f1ccc
Jul 19 16:58:20 lantea kernel: [14707.008026]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Jul 19 16:58:20 lantea kernel: [14707.008026] CR0: 80050033 CR2: b7702130 CR3: 318d6000 CR4: 000007e0
Jul 19 16:58:20 lantea kernel: [14707.008026] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
Jul 19 16:58:20 lantea kernel: [14707.008026] DR6: ffff0ff0 DR7: 00000400
Jul 19 16:58:20 lantea kernel: [14707.008026] Process dbus-daemon (pid: 20505, ti=f18f0000 task=f48dd8d0 task.ti=f18f0000)
Jul 19 16:58:20 lantea kernel: [14707.008026] Stack:
Jul 19 16:58:20 lantea kernel: [14707.008026]  c15bfa3d f18f1cdc ffffffff edd6e688 f18f1d40 c14c419c f48dd8d0 f48dd8d0
Jul 19 16:58:20 lantea kernel: [14707.008026]  00000000 00000000 edd6c3f8 00000000 00000001 00000000 f18f1d7c edd6c288
Jul 19 16:58:20 lantea kernel: [14707.008026]  00000000 00000000 ec7ff500 f18f1f4c 00000000 edd6c420 00000000 f4acd400
Jul 19 16:58:20 lantea kernel: [14707.008026] Call Trace:
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c15bfa3d>] ? _raw_spin_lock_irqsave+0x2d/0x40
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14c419c>] ? skb_queue_tail+0x3c/0x50
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c1289713>] ? aa_revalidate_sk+0x83/0x90
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14bd54c>] sock_recvmsg+0xcc/0x100
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c115f7c0>] ? __pollwait+0xd0/0xd0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c12c97b1>] ? _copy_from_user+0x41/0x60
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14c79cf>] ? verify_iovec+0x3f/0xb0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14bd480>] ? sock_sendmsg_nosec+0xf0/0xf0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14bcc70>] __sys_recvmsg+0x110/0x1d0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14bd480>] ? sock_sendmsg_nosec+0xf0/0xf0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c107d7cf>] ? trigger_load_balance+0x4f/0x1c0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c1074d7a>] ? scheduler_tick+0xda/0x100
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c12c5038>] ? timerqueue_add+0x58/0xb0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c1090255>] ? ktime_get+0x65/0xf0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c102cbab>] ? lapic_next_event+0x1b/0x20
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14be93b>] sys_recvmsg+0x3b/0x60
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c14bee3b>] sys_socketcall+0x28b/0x2d0
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c15c6f6e>] ? smp_apic_timer_interrupt+0x5e/0x8d
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c1064a28>] ? sys_clock_gettime+0x48/0x70
Jul 19 16:58:20 lantea kernel: [14707.008026]  [<c15c675f>] sysenter_do_call+0x12/0x28
Jul 19 16:58:20 lantea kernel: [14707.008026] Code: 6c ff ff ff 89 8d 74 ff ff ff 74 03 f0 ff 00 8b 95 74 ff ff ff 89 02 8b 95 6c ff ff ff 85 d2 0f 84 2d 01 00 00 8b 95 6c ff ff ff <f0> ff 02 89 55 84 8b 55 84 8b 8d 74 ff ff ff 89 51 04 8b 95 6c 
Jul 19 16:58:20 lantea kernel: [14707.008026] EIP: [<c154d2fb>] unix_stream_recvmsg+0x4eb/0x680 SS:ESP 0068:f18f1ccc
Jul 19 16:58:20 lantea kernel: [14707.537680] ---[ end trace 8455671fd435d7f5 ]---
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c1049ae5>] put_files_struct+0x75/0xc0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c1049bd6>] exit_files+0x46/0x60
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c104a01a>] do_exit+0x14a/0x7a0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c104473f>] ? print_oops_end_marker+0x2f/0x40
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c15c09dd>] oops_end+0x8d/0xd0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c10138d4>] die+0x54/0x80
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c15c05d2>] do_general_protection+0x102/0x180
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c113e61c>] ? kfree+0xcc/0xf0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14c3135>] ? skb_free_head+0x45/0x50
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c15c04d0>] ? do_trap+0xd0/0xd0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c15c0233>] error_code+0x67/0x6c
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14c007b>] ? proto_register+0x19b/0x210
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c154d2fb>] ? unix_stream_recvmsg+0x4eb/0x680
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c15bfa3d>] ? _raw_spin_lock_irqsave+0x2d/0x40
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14c419c>] ? skb_queue_tail+0x3c/0x50
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c1289713>] ? aa_revalidate_sk+0x83/0x90
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14bd54c>] sock_recvmsg+0xcc/0x100
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c115f7c0>] ? __pollwait+0xd0/0xd0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c12c97b1>] ? _copy_from_user+0x41/0x60
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14c79cf>] ? verify_iovec+0x3f/0xb0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14bd480>] ? sock_sendmsg_nosec+0xf0/0xf0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14bcc70>] __sys_recvmsg+0x110/0x1d0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14bd480>] ? sock_sendmsg_nosec+0xf0/0xf0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c107d7cf>] ? trigger_load_balance+0x4f/0x1c0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c1074d7a>] ? scheduler_tick+0xda/0x100
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c12c5038>] ? timerqueue_add+0x58/0xb0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c1090255>] ? ktime_get+0x65/0xf0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c102cbab>] ? lapic_next_event+0x1b/0x20
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14be93b>] sys_recvmsg+0x3b/0x60
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c14bee3b>] sys_socketcall+0x28b/0x2d0
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c15c6f6e>] ? smp_apic_timer_interrupt+0x5e/0x8d
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c1064a28>] ? sys_clock_gettime+0x48/0x70
Jul 19 16:58:21 lantea kernel: [14707.548025]  [<c15c675f>] sysenter_do_call+0x12/0x28
Jul 19 16:58:21 lantea kernel: [14707.548025] Code: e4 8b 53 20 89 45 e0 85 d2 74 0d 8d 45 e8 89 da e8 d3 ed ff ff 8b 45 e0 e8 bb 5d b1 ff 8b 4d e4 c7 45 e0 00 00 00 00 85 c9 74 11 <f0> ff 09 0f 94 c0 84 c0 74 07 89 c8 e8 0c fc b1 ff 8b 45 e8 c7 
Jul 19 16:58:21 lantea kernel: [14707.548025] EIP: [<c154bdf3>] unix_destruct_scm+0x53/0x90 SS:ESP 0068:f18f1abc
Jul 19 16:58:21 lantea kernel: [14708.492593] ---[ end trace 8455671fd435d7f6 ]---
Jul 19 16:58:21 lantea kernel: [14708.492613] Fixing recursive fault but reboot is needed!