[
https://issues.apache.org/jira/browse/ORC-586?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Zoltán Borók-Nagy updated ORC-586:
----------------------------------
Description:
StructColumnReader can leak memory if its constructor throws an exception.
StructColumnReader has a member vector<ColumnReader*> called 'children' which
is filled in the constructor:
[https://github.com/apache/orc/blob/c26ff4c351d7c34c4272442a6874703f510282a8/c%2B%2B/src/ColumnReader.cc#L874]
{noformat}
for(unsigned int i=0; i < type.getSubtypeCount(); ++i) {
const Type& child = *type.getSubtype(i);
if (selectedColumns[static_cast<uint64_t>(child.getColumnId())]) {
children.push_back(buildReader(child, stripe));
}
}
{noformat}
buildReader() returns a unique_ptr, but the constructor calls release() on it
which returns the underlying raw pointer and in the meantime the unique_ptr
releases the ownership.
StructColumnReader's destructor is supposed to invoke delete on these raw
pointers, but if an exception is thrown during the construction of a
StructColumnReader, then only the destructors of the member variables are
called. Therefore the vector gets destroyed, but the ColumnReader objects are
leaked.
The solution is to store unique_ptrs in the vector instead of raw pointers.
was:
StructColumnReader can leak memory if its constructor throws an exception.
StructColumnReader has a member vector<ColumnReader*> called 'children' which
is filled in the constructor:
[https://github.com/apache/orc/blob/c26ff4c351d7c34c4272442a6874703f510282a8/c%2B%2B/src/ColumnReader.cc#L874]
{noformat}
for(unsigned int i=0; i < type.getSubtypeCount(); ++i) { const
Type& child = *type.getSubtype(i); if
(selectedColumns[static_cast<uint64_t>(child.getColumnId())]) {
children.push_back(buildReader(child, stripe).release()); } }
{noformat}
buildReader() returns a unique_ptr, but the constructor calls release() on it
which returns the underlying raw pointer and in the meantime the unique_ptr
releases the ownership.
StructColumnReader's destructor is supposed to invoke delete on these raw
pointers, but if an exception is thrown during the construction of a
StructColumnReader, then only the destructors of the member variables are
called. Therefore the vector gets destroyed, but the ColumnReader objects are
leaked.
The solution is to store unique_ptrs in the vector instead of raw pointers.
> [C++] Memory leak in StructColumnReader
> ---------------------------------------
>
> Key: ORC-586
> URL: https://issues.apache.org/jira/browse/ORC-586
> Project: ORC
> Issue Type: Bug
> Reporter: Zoltán Borók-Nagy
> Priority: Major
>
> StructColumnReader can leak memory if its constructor throws an exception.
> StructColumnReader has a member vector<ColumnReader*> called 'children' which
> is filled in the constructor:
> [https://github.com/apache/orc/blob/c26ff4c351d7c34c4272442a6874703f510282a8/c%2B%2B/src/ColumnReader.cc#L874]
> {noformat}
> for(unsigned int i=0; i < type.getSubtypeCount(); ++i) {
> const Type& child = *type.getSubtype(i);
> if (selectedColumns[static_cast<uint64_t>(child.getColumnId())]) {
> children.push_back(buildReader(child, stripe));
> }
> }
> {noformat}
> buildReader() returns a unique_ptr, but the constructor calls release() on it
> which returns the underlying raw pointer and in the meantime the unique_ptr
> releases the ownership.
> StructColumnReader's destructor is supposed to invoke delete on these raw
> pointers, but if an exception is thrown during the construction of a
> StructColumnReader, then only the destructors of the member variables are
> called. Therefore the vector gets destroyed, but the ColumnReader objects are
> leaked.
> The solution is to store unique_ptrs in the vector instead of raw pointers.
>
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