James Clampffer created HDFS-9265:
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Summary: Use of undefined behavior in remote_block_reader causing
deterministic crashes.
Key: HDFS-9265
URL: https://issues.apache.org/jira/browse/HDFS-9265
Project: Hadoop HDFS
Issue Type: Sub-task
Reporter: James Clampffer
Priority: Blocker
The remote block reader relies on undefined behavior in how it uses
enable_shared_from_this.
http://en.cppreference.com/w/cpp/memory/enable_shared_from_this
The spec states a shared_ptr to an object inheriting from
enable_shared_from_this must be live before calling make_shared_from_this.
Calling make_shared_from_this without an existing shared_ptr is undefined
behavior and causes deterministic crashes when the code is built with GCC.
example:
class foo : public enable_shared_from_this {/*bar*/};
safe:
auto ptr1 = std::make_shared<foo>();
auto ptr2 = foo->make_shared_from_this();
broken:
foo *ptr = new foo();
auto ptr2 = foo->make_shared_from_this(); //no existing live shared_ptr
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