Re: Xen 4.2.1 live migration with qemu device model

[Alex Bligh <alex@alex.org.uk>]

This particular segv seems to be because in
  libxl__domain_suspend_common_switch_qemu_logdirty
in libxl_dom.c the variables 'got', and 'got_ret' do not appear to be initialised
to NULL (got certainly should be, got_ret should be if there is any possibility
of libxl__xs_read_checked not writing to got_ret which it doesn't seem to be).
Code inspection suggests this issue is still there in 4.2.1, hence my wondering
whether other stuff needs bringing in from unstable.


--On 11 December 2012 11:45:42 +0000 Alex Bligh <alex@alex.org.uk> wrote:

> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7fffeffff700 (LWP 5995)]
> 0x00007ffff5a0862a in ?? () from /lib/x86_64-linux-gnu/libc.so.6
> (gdb) bt
># 0  0x00007ffff5a0862a in ?? () from /lib/x86_64-linux-gnu/libc.so.6
># 1  0x00007ffff6d4e970 in libxl__domain_suspend_common_switch_qemu_logdirty (domid=<optimized out>, enable=<optimized out>, user=0x7ffff00024e8) at libxl_dom.c:728
># 2  0x00007ffff6d5c1ae in libxl__srm_callout_received_save (msg=0x7fffefffe41a " error", len=<optimized out>, user=0x7ffff00024e8) at _libxl_save_msgs_callout.c:162
># 3  0x00007ffff6d5b736 in helper_stdout_readable (egc=0x7fffefffe5a0, ev=0x7ffff0002560, fd=38, events=<optimized out>, revents=<optimized out>) at libxl_save_callout.c:283
># 4  0x00007ffff6d601f1 in afterpoll_internal (egc=0x7fffefffe5a0, poller=0x7ffff00028c0, nfds=4, fds=0x7ffff00048b0, now=...) at libxl_event.c:948
># 5  0x00007ffff6d604db in eventloop_iteration (egc=0x7fffefffe5a0, poller=0x7ffff00028c0) at libxl_event.c:1368
># 6  0x00007ffff6d616b3 in libxl__ao_inprogress (ao=0x7ffff0001d40, file=<optimized out>, line=<optimized out>, func=<optimized out>) at libxl_event.c:1614
># 7  0x00007ffff6d3ab75 in libxl_domain_suspend (ctx=<optimized out>, domid=1, fd=10, flags=<optimized out>, ao_how=<optimized out>) at libxl.c:796
># 8  0x000000000043677e in migrate_domain_send (ctx=0x7ffff0008860, domid=1, fd=10) at hypervisor/xen_libxl.c:587
># 9  0x000000000043698a in live_migrate_send (hyperconn=0x7ffff0001c70, server=0x7ffff0001cb0, node_ip=0x7ffff00041e0 "10.157.128.20", fd=10) at hypervisor/xen_libxl.c:647
># 10 0x0000000000422a70 in migrate_server_action (request=0x7ffff0002980) at action/node_action.c:1287
># 11 0x00000000004240c1 in runAction (socket_fd=8) at action/handleaction.c:138
># 12 0x00000000004179bd in runcomm (socket=0x8) at xvpagent.c:253
># 13 0x0000000000427502 in trackedthread_run (arg=0x66df20) at util/util.c:179
># 14 0x00007ffff5c9ce9a in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
># 15 0x00007ffff59ca4bd in clone () from /lib/x86_64-linux-gnu/libc.so.6
># 16 0x0000000000000000 in ?? ()



-- 
Alex Bligh