BUG: kvm crashing in void librbd::AioCompletion::complete_request

[Stefan Priebe <s.priebe@profihost.ag>]

Hello,

while benchmarking the new v2 rbd format i saw several crashes of KVM. 
First i thought this was kernel related but i was just happening faster 
with one kernel than the other.

The KVM crash / exit looks like this:
librbd/AioCompletion.cc: In function 'void 
librbd::AioCompletion::complete_request(CephContext*, ssize_t)' thread 
7f73db67c780 time 2012-11-04 14:59:44.997009
librbd/AioCompletion.cc: 43: FAILED assert(bl.length() == read_buf_len)
  ceph version 0.53-585-ga01b112 (a01b112d71a0b6a1bb206d53867d13536d17bbf6)
  1: (librbd::AioCompletion::complete_request(CephContext*, long)+0xa89) 
[0x7f73d9337319]
  2: (librbd::C_AioRead::finish(int)+0x174) [0x7f73d93374e4]
  3: (Context::complete(int)+0xa) [0x7f73d933796a]
  4: (librbd::C_CacheRead::finish(int)+0xe) [0x7f73d933683e]
  5: (Context::complete(int)+0xa) [0x7f73d933796a]
  6: (librbd::ImageCtx::aio_read_from_cache(object_t, 
ceph::buffer::list*, unsigned long, unsigned long, Context*)+0x3a0) 
[0x7f73d9347bd0]
  7: (librbd::aio_read(librbd::ImageCtx*, std::vector<std::pair<unsigned 
long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned 
long> > > const&, char*, ceph::buffer::list*, 
librbd::AioCompletion*)+0x765) [0x7f73d9354995]
  8: (librbd::aio_read(librbd::ImageCtx*, unsigned long, unsigned long, 
char*, ceph::buffer::list*, librbd::AioCompletion*)+0xa2) [0x7f73d9354f92]
  9: (()+0x9f2de) [0x7f73db73d2de]
  10: (()+0x9f490) [0x7f73db73d490]
  11: (()+0x83c45) [0x7f73db721c45]
  12: (()+0x850ea) [0x7f73db7230ea]
  NOTE: a copy of the executable, or `objdump -rdS <executable>` is 
needed to interpret this.
terminate called after throwing an instance of 'ceph::FailedAssertion'

Stefan