repeating the test -- I do not see an OOPS again, but a series of GPFs:


[  645.729741] ptrace of non-child pid 26873 was attempted by: gdb (pid 26875)
[  646.187877] ptrace of non-child pid 26895 was attempted by: gdb (pid 26897)
[  650.811770] ptrace of non-child pid 27075 was attempted by: dac-bypass.py (pid 27076)
[  657.211168] ptrace of non-child pid 27253 was attempted by: dac-bypass.py (pid 27256)
[  661.757066] general protection fault: 0000 [#5] SMP 
[  661.757086] Modules linked in: acpiphp [last unloaded: signpost]
[  661.757097] 
[  661.757103] Pid: 27363, comm: seccomp_tests Tainted: G      D     3.0.0-23-virtual #39-Ubuntu  
[  661.757114] EIP: 0061:[<c010372d>] EFLAGS: 00010202 CPU: 0
[  661.757125] EIP is at xen_write_cr4+0xd/0x20
[  661.757130] EAX: 00000664 EBX: 00000016 ECX: c08b4740 EDX: 00000000
[  661.757137] ESI: eb115940 EDI: b76c7bb0 EBP: eb285f60 ESP: eb285f60
[  661.757144]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0069
[  661.757151] Process seccomp_tests (pid: 27363, ti=eb284000 task=eb115940 task.ti=eb284000)
[  661.757159] Stack:
[  661.757163]  eb285f68 c0110bc6 eb285f70 c01116f5 eb285f7c c01b6868 00000001 eb285fac
[  661.757178]  c01676cc b76c7bb0 00000000 c1204080 000003e8 eb285fac c016646a d067b9f3
[  661.757192]  00000016 b76c7bb0 00000000 eb284000 c065f644 00000016 00000001 0804bd41
[  661.757207] Call Trace:
[  661.757216]  [<c0110bc6>] hard_disable_TSC+0x16/0x20
[  661.757224]  [<c01116f5>] disable_TSC+0x25/0x30
[  661.757231]  [<c01b6868>] prctl_set_seccomp+0x38/0x60
[  661.757239]  [<c01676cc>] sys_prctl+0xbc/0x300
[  661.757247]  [<c016646a>] ? sys_setresuid+0x10a/0x150
[  661.757256]  [<c065f644>] syscall_call+0x7/0xb
[  661.757261] Code: e5 3e 8d 74 26 00 5d c3 8d b6 00 00 00 00 55 89 e5 3e 8d 74 26 00 31 c0 5d c3 8d 74 26 00 55 89 e5 3e 8d 74 26 00 25 6f ff fb ff <0f> 22 e0 5d c3 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 55 89 
[  661.757335] EIP: [<c010372d>] xen_write_cr4+0xd/0x20 SS:ESP 0069:eb285f60
[  661.757356] ---[ end trace 613d93ce9b9bb40f ]---
[  661.757812] general protection fault: 0000 [#6] SMP 
[  661.757822] Modules linked in: acpiphp [last unloaded: signpost]
[  661.757831] 
[  661.757835] Pid: 27364, comm: seccomp_tests Tainted: G      D     3.0.0-23-virtual #39-Ubuntu  
[  661.757846] EIP: 0061:[<c010372d>] EFLAGS: 00010202 CPU: 0
[  661.757853] EIP is at xen_write_cr4+0xd/0x20
[  661.757859] EAX: 00000664 EBX: 00000016 ECX: c08b4740 EDX: 00000000
[  661.757865] ESI: eb116600 EDI: b76c7bb0 EBP: c120ff60 ESP: c120ff60
[  661.757871]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0069
[  661.757878] Process seccomp_tests (pid: 27364, ti=c120e000 task=eb116600 task.ti=c120e000)
[  661.757885] Stack:
[  661.757889]  c120ff68 c0110bc6 c120ff70 c01116f5 c120ff7c c01b6868 00000001 c120ffac
[  661.757903]  c01676cc b76c7bb0 00000000 c1204880 000003e8 c120ffac c016646a 80bf79e9
[  661.757918]  00000016 b76c7bb0 00000000 c120e000 c065f644 00000016 00000001 0804c06b
[  661.757932] Call Trace:
[  661.757938]  [<c0110bc6>] hard_disable_TSC+0x16/0x20
[  661.757945]  [<c01116f5>] disable_TSC+0x25/0x30
[  661.757952]  [<c01b6868>] prctl_set_seccomp+0x38/0x60
[  661.757959]  [<c01676cc>] sys_prctl+0xbc/0x300
[  661.757966]  [<c016646a>] ? sys_setresuid+0x10a/0x150
[  661.757973]  [<c065f644>] syscall_call+0x7/0xb
[  661.757979] Code: e5 3e 8d 74 26 00 5d c3 8d b6 00 00 00 00 55 89 e5 3e 8d 74 26 00 31 c0 5d c3 8d 74 26 00 55 89 e5 3e 8d 74 26 00 25 6f ff fb ff <0f> 22 e0 5d c3 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 55 89 
[  661.758051] EIP: [<c010372d>] xen_write_cr4+0xd/0x20 SS:ESP 0069:c120ff60
[  661.758064] ---[ end trace 613d93ce9b9bb410 ]---
[  661.832828] seccomp_tests[27370]: system call 6 (sys_close) blocked at 0xb77b2416
[  661.834385] seccomp_tests[27374]: system call 1 (sys_exit) blocked at 0xb77b2416
[  661.835191] seccomp_tests[27376]: system call 1 (sys_exit) blocked at 0xb77b2416
[  661.837150] seccomp_tests[27380]: system call 11 (unknown) blocked at 0xb77b2416
[  661.837577] seccomp_tests[27381]: system call 11 (unknown) blocked at 0xb77b2416