Pkg xen devel - Apr 2014 - Bug#744930: Failed migration from 4.3 to 4.1 crashes VM on sender

Package: xen
Version: 4.3.0-3+b1

When trying to migrate from a 4.3 host to a 4.1 host (which should fail
of course, but gracefully), the PV guest on the sending host crashes.

To be honest, I have no idea which component to file this bug against.
The sending host has been upgraded to jessie. Here're the relevant package
versions:

ii  libxen-4.3                          4.3.0-3+b1                   amd64      
Public libs for Xen
ii  libxen-dev                          4.3.0-3+b1                   amd64      
Public headers and libs for Xen
ii  libxenstore3.0                      4.3.0-3+b1                   amd64      
Xenstore communications library for Xen
ii  xen-hypervisor-4.3-amd64            4.3.0-3+b1                   amd64      
Xen Hypervisor on AMD64
ii  xen-system-amd64                    4.3.0-3+b1                   amd64      
Xen System on AMD64 (meta-package)
ii  xen-utils-4.3                       4.3.0-3+b1                   amd64      
XEN administrative tools
ii  xen-utils-common                    4.3.0-3                      all        
Xen administrative tools - common files
ii  xenstore-utils                      4.3.0-3+b1                   amd64      
Xenstore utilities for Xen



Output from xl migrate:

libxl: error: libxl_utils.c:393:libxl_read_exactly: file/stream truncated
reading ready message from migration receiver stream
Migration failed, resuming at sender.

Output from crashed VM:

[69204.815336] kernel BUG at
/build/buildd-linux-2.6_2.6.32-31-amd64-vrfdM4/linux-2.6-2.6.32/debian/build/source_amd64_xen/drivers/xen/events.c:1245!
[69204.815336] invalid opcode: 0000 [#1] SMP
[69204.815336] last sysfs file: /sys/devices/virtual/net/lo/operstate
[69204.815336] CPU 0
[69204.815336] Modules linked in: dm_snapshot dm_mirror dm_region_hash dm_log
snd_pcm snd_timer snd soundcore snd_page_alloc pcspkr evdev xfs exportfs dm_mod
xen_blkfront xen_netfront
[69204.815336] Pid: 9975, comm: kstop/0 Not tainted 2.6.32-5-xen-amd64 #1
[69204.815336] RIP: e030:[<ffffffff811f2384>]  [<ffffffff811f2384>]
xen_irq_resume+0x10c/0x2bb
[69204.815336] RSP: e02b:ffff88001f005d40  EFLAGS: 00010082
[69204.815336] RAX: ffffffffffffffef RBX: 0000000000000000 RCX: 0000000000000001
[69204.815336] RDX: ffff8800033c8000 RSI: 00000000ffffffef RDI: 0000000000000001
[69204.815336] RBP: 0000000000000000 R08: 0000000000000200 R09: ffff88001f005db0
[69204.815336] R10: ffffe8fffffe8128 R11: ffff88001fca2000 R12: 00000000000001ff
[69204.815336] R13: 0000000000000000 R14: 0000000000012b00 R15: 0000000000012aa0
[69204.815336] FS:  00007fac890a5750(0000) GS:ffff8800033c8000(0000)
knlGS:0000000000000000
[69204.815336] CS:  e033 DS: 0000 ES: 0000 CR0: 000000008005003b
[69204.815336] CR2: 00007f58a09a61c8 CR3: 000000001e4f8000 CR4: 0000000000002660
[69204.815336] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[69204.815336] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[69204.815336] Process kstop/0 (pid: 9975, threadinfo ffff88001f004000, task
ffff88001dcbea60)
[69204.815336] Stack:
[69204.815336]  ffff8800033d9d70 0000000000000000 ffffffff811f10f8
ffff88001f005d90
[69204.815336] <0> 0000000000000000 ffffffff810e831c 0000000000000000
ffff88001fd58620
[69204.815336] <0> ffff88001fca2000 00000000000067f9 ffffffff8100e63d
ffffffff8100ecf2
[69204.815336] Call Trace:
[69204.815336]  [<ffffffff811f10f8>] ? gnttab_map+0x105/0x112
[69204.815336]  [<ffffffff810e831c>] ? kfree+0xc6/0xcb
[69204.815336]  [<ffffffff8100e63d>] ? xen_force_evtchn_callback+0x9/0xa
[69204.815336]  [<ffffffff8100ecf2>] ? check_events+0x12/0x20
[69204.815336]  [<ffffffff811f3980>] ? xen_suspend+0xaf/0xc4
[69204.815336]  [<ffffffff8108bd2a>] ? stop_cpu+0x83/0xc6
[69204.815336]  [<ffffffff81062887>] ? worker_thread+0x188/0x21d
[69204.815336]  [<ffffffff8108bca7>] ? stop_cpu+0x0/0xc6
[69204.815336]  [<ffffffff81065eb2>] ? autoremove_wake_function+0x0/0x2e
[69204.815336]  [<ffffffff810626ff>] ? worker_thread+0x0/0x21d
[69204.815336]  [<ffffffff81065be5>] ? kthread+0x79/0x81
[69204.815336]  [<ffffffff81012baa>] ? child_rip+0xa/0x20
[69204.815336]  [<ffffffff81011d61>] ? int_ret_from_sys_call+0x7/0x1b
[69204.815336]  [<ffffffff8101251d>] ? retint_restore_args+0x5/0x6
[69204.815336]  [<ffffffff81012ba0>] ? child_rip+0x0/0x20
[69204.815336] Code: fe 0f b7 40 08 39 e8 74 04 0f 0b eb fe 48 8d 74 24 70 bf 01
00 00 00 89 6c 24 70 44 89 6c 24 74 e8 c3 f9 ff ff 85 c0 89 c6 74 04 <0f>
0b eb fe 8b 5c 24 78 48 8b 05 75 66 49 00 b9 04 00 00 00 48
[69204.815336] RIP  [<ffffffff811f2384>] xen_irq_resume+0x10c/0x2bb
[69204.815336]  RSP <ffff88001f005d40>
[69204.815336] ---[ end trace 45b15f10b39c02ad ]---
[69204.815336] ------------[ cut here ]------------
[69204.815336] WARNING: at
/build/buildd-linux-2.6_2.6.32-31-amd64-vrfdM4/linux-2.6-2.6.32/debian/build/source_amd64_xen/kernel/time/timekeeping.c:249
ktime_get+0x22/0xb7()
[69204.815336] Modules linked in: dm_snapshot dm_mirror dm_region_hash dm_log
snd_pcm snd_timer snd soundcore snd_page_alloc pcspkr evdev xfs exportfs dm_mod
xen_blkfront xen_netfront
[69204.815336] Pid: 0, comm: swapper Tainted: G      D    2.6.32-5-xen-amd64 #1
[69204.815336] Call Trace:
[69204.815336]  [<ffffffff8106d48b>] ? ktime_get+0x22/0xb7
[69204.815336]  [<ffffffff8106d48b>] ? ktime_get+0x22/0xb7
[69204.815336]  [<ffffffff8104ef10>] ? warn_slowpath_common+0x77/0xa3
[69204.815336]  [<ffffffff8106d48b>] ? ktime_get+0x22/0xb7
[69204.815336]  [<ffffffff810719c1>] ?
tick_nohz_stop_sched_tick+0x6f/0x335
[69204.815336]  [<ffffffff81010e82>] ? cpu_idle+0x73/0xda
[69204.815336]  [<ffffffff81509cdd>] ? start_kernel+0x3dc/0x3e8
[69204.815336]  [<ffffffff8150bc93>] ? xen_start_kernel+0x586/0x58a
[69204.815336] ---[ end trace 45b15f10b39c02ae ]---