Add locking around AbstractSessionContext JNI. #1154
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We don't have a definitive root cause for google#1131 but it seems like either use-after-free (e.g. finalizer ordering) or concurrency issue, so: 1. Make the native pointer private and move all accesses into AbstractSessionContext 2. Zero it out on finalisation 3. Add locking. Note we only need a read lock for the sslNew() path as this is thread safe and doesn't modify the native SSL_CTX aside from atomic refcounts. The above change is broadly equivalent to turning the native pointer into a NativeRef, which would mean its finalizer shouldn't run until after the AbstractSessionContext object is unreachable, but (currently) NativeRefs don't zero out the native address on finalization.
Yqwed
approved these changes
Aug 4, 2023
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We don't have a definitive root cause for #1131 but it seems like either use-after-free (e.g. finalizer ordering) or concurrency issue, so:
The above change is broadly equivalent to turning the native pointer into a NativeRef, which would mean its finalizer shouldn't run until after the AbstractSessionContext object is unreachable, but (currently) NativeRefs don't zero out the native address on finalization.