Re: Problem with (?) hardened-sources-3.15.x on kvm-vm

W dniu 29.08.2014 o 01:13, Alex Xu pisze:
> On 28/08/14 05:02 PM, Sven Vermeulen wrote:
>> On Wed, Aug 27, 2014 at 05:34:20PM +0100, André Aparício wrote:
>>> I encountered the same problem with qemu/kvm but can't even login, I
>>> get random segfaults and even failed malloc assertions
>>> in /sbin/init, /sbin/rc or /bin/login (never past this).
>>>
>>> But it works fine with CONFIG_PAX_MEMORY_UDEREF disabled.
>>
>> I am not able to reproduce this :-(
>>
>> Host and guest are both on 3.15.5-hardened-r2 and both have UDEREF enabled.
>>
>> I tried emerging boost on the guest as recommended in another post but this
>> didn't fail.
>>
>> Wkr,
>>   Sven Vermeulen
>>
> 
> My VM has 12 CPUs but I use MAKEOPTS=-j3. Maybe this affects
> reproducibility.
> 
> My host is of unknown kernel, but I'm pretty sure it's not Gentoo, let
> alone Hardened.
> 
> Also, I am using <cpu mode="host-passthrough"/> in libvirt (equivalent
> to -cpu host in qemu opts), so PAX detects PCID and enables strong
> UDEREF. I will try with pax_weakuderef as soon as I get a chance to
> reboot the VM.

Fabulous "me too", I've got <cpu mode='host-model'> and guest have PCID
available:
dmesg |grep PCID
[    0.020000] PAX: PCID detected
[    0.020000] PAX: PCID detected
[    0.020000] PAX: PCID detected


Snip from cpuinfo of guest:
processor       : 2
vendor_id       : GenuineIntel
cpu family      : 6
model           : 42
model name      : Intel Xeon E312xx (Sandy Bridge)
stepping        : 1
microcode       : 0x1
cpu MHz         : 3292.514
cache size      : 4096 KB
physical id     : 2
siblings        : 1
core id         : 0
cpu cores       : 1
apicid          : 2
initial apicid  : 2
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx rdtscp lm
constant_tsc arch_perfmon rep_good nopl eagerfpu pni pclmulqdq ssse3
cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx
f16c rdrand hypervisor lahf_lm xsaveopt fsgsbase smep erms
bogomips        : 6585.02
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management: