[Xen-devel] 100% reliable Oops on xen 4.0.1

[Peter Moody <pmoody@xxxxxxxxxx>]

This seems to be some combination of Xen and the audit subsystem, but
the attached program crashes my machine 100% of the time.

steps to reproduce the crash:

 *  1) compile with gcc -m32
 *  2) start auditd, install any rule (I've only tested syscall
auditing, but any syscall seems to work).
 *     /etc/init.d/auditd start ; auditctl -D ; auditctl -a
exit,always -F arch=64 -S chmod
 *  3) run'n wait (this only loops twice for me before dying)
 *     ./a.out
 *  4) bask in instantaneous kernel oops.

here's xm info from dom0

[xen2.atl] root@gntb1:~# xm info
host                   : gntb1.atl.corp.google.com
release                : 3.2.13-ganeti-rx6-xen0
version                : #1 SMP Thu Jun 7 12:59:40 CEST 2012
machine                : x86_64
nr_cpus                : 12
nr_nodes               : 2
cores_per_socket       : 6
threads_per_core       : 1
cpu_mhz                : 2660
hw_caps                :
bfebfbff:2c100800:00000000:00001f40:029ee3ff:00000000:00000001:00000000
virt_caps              : hvm
total_memory           : 32755
free_memory            : 22665
node_to_cpu            : node0:0,2,4,6,8,10
                         node1:1,3,5,7,9,11
node_to_memory         : node0:13083
                         node1:9582
node_to_dma32_mem      : node0:0
                         node1:3235
max_node_id            : 1
xen_major              : 4
xen_minor              : 0
xen_extra              : .1
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32
hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : unavailable
xen_commandline        : placeholder dom0_mem=1024M loglvl=all
com1=115200,8n1 console=com1 iommu=0
cc_compiler            : gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
cc_compile_by          : pmacedo
cc_compile_domain      : google.com
cc_compile_date        : Wed Mar 16 15:24:06 UTC 2011
xend_config_format     : 4

I'm not sure what you need from the domU. It's running 2.6.38.8 (but
I've seen this bug all the way up to 3.5.0-rc7, the latest I've
tested). It's a fairly beefy setup, 32G memory and 6 cpus.

I suspect xen as opposed to auditd because:

 a) this only happens on our xen machines (though not all of them)
 b) one of my stack traces started with

[172577.560441]  [<ffffffff810065ad>] ? xen_force_evtchn_callback+0xd/0x10

Any one have any idea what's going on?

Cheers,
peter

-- 
Peter Moody      Google    1.650.253.7306
Security Engineer  pgp:0xC3410038

Attachment: crasher.c
Description: Text Data

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel