leezu commented on issue #18314:
URL:
https://github.com/apache/incubator-mxnet/issues/18314#issuecomment-628821443
The mutex in above core dump is actually non existant. The problem here is
that the ffi call to MXNDArraySyncCopyToCPU passes a handle whose Chunk was
cleaned up. So the segfault is just a symptom of memory and reference
management issues.
the array
```
(gdb) p *this
$6 = {ptr_ = std::shared_ptr<mxnet::NDArray::Chunk> (use count 1645762192,
weak count 22028) = {get() = 0x560d62a70cb0}, shape_ = {<mxnet::Tuple<long>> =
{static kStackCache = 4, ndim_ = 2,
num_heap_allocated_ = 0, data_stack_ = {10, 10, -3617008641903833651,
-3617008641903833651}, data_heap_ = 0x0}, <No data fields>}, byte_offset_ = 0,
dtype_ = 0, reuse_ = false,
storage_type_ = mxnet::kDefaultStorage, autograd_entry_ = {node =
std::shared_ptr<nnvm::Node> (use count 1647685840, weak count 22028) = {get() =
0x560d622fe220}, index = 0, version = 0},
deferredcompute_entry_ = {node = std::shared_ptr<nnvm::Node> (empty) =
{get() = 0x0}, index = 0, version = 0}, tblob_ = {dptr_ = 0x0, shape_ =
{<mxnet::Tuple<long>> = {static kStackCache = 4,
ndim_ = -1, num_heap_allocated_ = 0, data_stack_ =
{-3617008641903833651, -2459565876494606899, -2459565876494606883,
-2459565876494606883}, data_heap_ = 0x0}, <No data fields>}, type_flag_ = 0,
dltensor_ = {data = 0x0, ctx = {device_type = kDLCPU, device_id = 0},
ndim = -1, dtype = {code = 2 '\002', bits = 32 ' ', lanes = 1}, shape =
0x560d62188f78, strides = 0x0, byte_offset = 0}}}
```
and the chunk
```
p *ptr_
$4 = {shandle = {dptr = 0xdddddddddddddddd, size = 481, ctx = {dev_type =
1655088448, dev_id = 22029, static kMaxDevType = 6, static kMaxDevID = 16},
shared_pid = 1645776592, shared_id = 22029,
profiler_scope = Python Exception <class 'OverflowError'> int too big to
convert:
, Python Exception <class 'OverflowError'> int too big to convert:
name = }, aux_handles = std::vector of length 0, capacity 0, mkl_mem_ =
<error reading variable: Cannot access memory at address 0xdddddddddddddde5>,
var = 0xdddddddddddddddd,
static_data = 221, delay_alloc = 221, storage_type = -572662307, aux_types
= std::vector of length 0, capacity 0, ctx = {dev_type = 3722304989, dev_id =
-572662307, static kMaxDevType = 6,
static kMaxDevID = 16}, storage_shape = {<mxnet::Tuple<long>> = {static
kStackCache = 4, ndim_ = -572662307, num_heap_allocated_ = -572662307,
data_stack_ = {-2459565876494606883,
-2459565876494606883, -2459565876494606883, -2459565876494606883},
data_heap_ = 0xdddddddddddddddd}, <No data fields>}, aux_shapes = std::vector
of length 0, capacity 0,
storage_ref_ = <error reading variable: Cannot access memory at address
0xdddddddddddddde5>, engine_ref_ = <error reading variable: Cannot access
memory at address 0xdddddddddddddde5>}
```
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
