Error is caused by: image = rbd.Image(ioctx, image_id)

Ceph Librbd error

common/Mutex.cc: In function 'void Mutex::Lock(bool)' thread 7f07412ee740 time 2014-07-24 15:55:06.142131
common/Mutex.cc: 93: FAILED assert(r == 0)
 ceph version 0.80.1 (a38fe1169b6d2ac98b427334c12d7cf81f809b74)
 1: (Mutex::Lock(bool)+0x111) [0x7f073a2089e1]
 2: (librados::IoCtxImpl::unwatch(object_t const&, unsigned long)+0xdc) [0x7f073a199fec]
 3: (librados::IoCtx::unwatch(std::string const&, unsigned long)+0x2a) [0x7f073a16b1fa]
 4: (librbd::ImageCtx::unregister_watch()+0x33) [0x7f0723d486c3]
 5: (librbd::close_image(librbd::ImageCtx*)+0x8a) [0x7f0723d5d0ca]
 6: (rbd_close()+0x9) [0x7f0723d40749]
 7: (ffi_call_unix64()+0x4c) [0x7f073f8ecadc]
 8: (ffi_call()+0x1fc) [0x7f073f8ec40c]
 9: (_ctypes_callproc()+0x48e) [0x7f073fb035fe]
 10: (()+0x15f9e) [0x7f073fb04f9e]
 11: (PyEval_EvalFrameEx()+0x979) [0x561669]
 12: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 13: /home/dan/Code/portal/env/bin/python() [0x556cea]
 14: /home/dan/Code/portal/env/bin/python() [0x4b5164]
 15: /home/dan/Code/portal/env/bin/python() [0x4bc22f]
 16: /home/dan/Code/portal/env/bin/python() [0x4bcbeb]
 17: /home/dan/Code/portal/env/bin/python() [0x5413e3]
 18: (PyEval_EvalFrameEx()+0xcb3) [0x5619a3]
 19: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 20: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 21: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 22: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 23: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 24: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 25: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 26: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 27: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 28: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 29: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 30: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 31: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 32: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 33: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 34: (PyEval_EvalFrameEx()+0x7ed) [0x5614dd]
 35: /home/dan/Code/portal/env/bin/python() [0x556cea]
 36: /home/dan/Code/portal/env/bin/python() [0x4b5164]
 37: /home/dan/Code/portal/env/bin/python() [0x4becd4]
 38: (PyEval_EvalFrameEx()+0x979) [0x561669]
 39: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 40: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 41: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 42: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 43: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 44: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 45: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 46: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 47: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 48: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 49: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 50: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 51: (PyEval_EvalFrameEx()+0xc9a) [0x56198a]
 52: /home/dan/Code/portal/env/bin/python() [0x556cea]
 53: (PyEval_EvalFrameEx()+0x22f1) [0x562fe1]
 54: /home/dan/Code/portal/env/bin/python() [0x556cea]
 55: (PyEval_EvalFrameEx()+0x22f1) [0x562fe1]
 56: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 57: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 58: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 59: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 60: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 61: (PyEval_EvalFrameEx()+0x1a06) [0x5626f6]
 62: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 63: (PyEval_EvalFrameEx()+0x7ed) [0x5614dd]
 64: (PyEval_EvalCodeEx()+0x2a4) [0x54b7d4]
 65: /home/dan/Code/portal/env/bin/python() [0x55830c]
 66: (PyRun_FileExFlags()+0x92) [0x468567]
 67: (PyRun_SimpleFileExFlags()+0x2ee) [0x468aa0]
 68: (Py_Main()+0xb5e) [0x46a1e3]
 69: (__libc_start_main()+0xf5) [0x7f0740b33ec5]
 70: /home/dan/Code/portal/env/bin/python() [0x5735fe]
 NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to interpret this.
terminate called after throwing an instance of 'ceph::FailedAssertion'