Fixed memory bug: properly root repeated/map field when assigning. #8639
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Previously the protobuf extension would not properly root memory from a repeated field or map when assigning to a message field (see the attached test case). This could cause crashes if the repeated field is subsequently accessed.
fowles
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May 22, 2021
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JDK failure is unrelated. Merging. |
stanhu
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May 24, 2021
google-protobuf 3.15.x has a bug that causes a seg fault in Ruby under certain conditions (protocolbuffers/protobuf#8639). Use google-protobuf 3.17.1 instead.
lfittl
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May 24, 2021
google-protobuf 3.15.x has a bug that causes a seg fault in Ruby under certain conditions (protocolbuffers/protobuf#8639). Use google-protobuf 3.17.1 instead.
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Previously the protobuf extension would not properly root memory from a repeated field or map when assigning to a message field (see the attached test case). If there is no direct reference to the repeated field from Ruby, this will result in a memory error if there is a GC and the repeated field is subsequently accessed (for example, in
#encode).The fix is to do the appropriate
upb_arena_fuse()operation when this assignment is performed. This will cause the Union/Find machinery to ensure that the memory for the repeated field or map lives as long as the message.The the new test case does not actually crash on my machine, but it does trigger a Valgrind error that I can confirm is fixed by the code in this PR. In the future we should make sure that our CI tests are running tests under Valgrind so we can catch future memory errors of this kind.
Also added an explicit check that
upb_arena_fuse()succeeded. This is not related to the bugfix, but it is another measure to help ensure that the memory model of the extension is correct.Fixes: #8559