Recover from panic in HandleTransaction to prevent peer crash (backport #5472)#5473
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When a transaction times out during a range query, the timeout path closes LevelDB iterators while the handler goroutine is still using them, causing a nil pointer dereference that crashes the peer. Add a deferred recover() in HandleTransaction to catch such panics and return an error response instead of crashing. This is safe because the transaction has already timed out and the resources are being freed. The panic value is logged but not included in the response payload to avoid violating endorsement determinism across peers. Metrics are recorded in the recover path to match the normal code path. Also adds regression tests that verify the panic is recovered and an error response is sent. Fixes #5048 Signed-off-by: Jaskirat-s7 <jaskiratsingh7812@gmail.com> (cherry picked from commit 6a67397)
pfi79
approved these changes
May 7, 2026
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Summary
When a transaction times out during a range query, the timeout path in
Execute()closes LevelDB iterators viaCloseQueryIterators()while the handler goroutine (spawned byhandleMessageReadyState) is still actively callingiter.Next(). This causes a nil pointer dereference in the LevelDB iterator that crashes the peer process.Changes
recover()inHandleTransaction(core/chaincode/handler.go) to catch panics from concurrent iterator access and return an error response instead of crashing the peerTesting
All 320 existing tests pass, including the 2 new regression tests:
This is an automatic backport of pull request #5472 done by [Mergify](https://mergify.com).