fix: free rust traces that never make it to CCC (#844)

params/version.go

@@ -24,7 +24,7 @@ import (
 const (
 	VersionMajor = 5         // Major version component of the current release
 	VersionMinor = 4         // Minor version component of the current release
-	VersionPatch = 6         // Patch version component of the current release
+	VersionPatch = 7         // Patch version component of the current release
 	VersionMeta  = "mainnet" // Version metadata to append to the version string
 )
 

rollup/circuitcapacitychecker/impl.go

@@ -223,3 +223,7 @@ func MakeRustTrace(trace *types.BlockTrace, buffer *bytes.Buffer) unsafe.Pointer
 
 	return C.parse_json_to_rust_trace(tracesStr)
 }
+
+func FreeRustTrace(ptr unsafe.Pointer) {
+	C.free_rust_trace(ptr)
+}

rollup/circuitcapacitychecker/libzkp/libzkp.h

@@ -9,4 +9,5 @@ char* apply_block(uint64_t id, void* block_trace);
 char* get_tx_num(uint64_t id);
 char* set_light_mode(uint64_t id, bool light_mode);
 void free_c_chars(char* ptr);
-void* parse_json_to_rust_trace(char* trace_json_ptr);
+void* parse_json_to_rust_trace(char* trace_json_ptr);
+void free_rust_trace(void* trace_ptr);

rollup/circuitcapacitychecker/libzkp/src/lib.rs

@@ -271,6 +271,7 @@ pub mod utils {
     use std::ffi::{CStr, CString};
     use std::os::raw::c_char;
     use std::str::Utf8Error;
+    use prover::BlockTrace;
 
     /// # Safety
     #[no_mangle]
@@ -283,6 +284,13 @@ pub mod utils {
         let _ = CString::from_raw(ptr);
     }
 
+    /// # Safety
+    #[no_mangle]
+    pub unsafe extern "C" fn free_rust_trace(trace_ptr: *mut BlockTrace) {
+        let _ = Box::from_raw(trace_ptr);
+    }
+
+
     #[allow(dead_code)]
     pub(crate) fn c_char_to_str(c: *const c_char) -> Result<&'static str, Utf8Error> {
         let cstr = unsafe { CStr::from_ptr(c) };

rollup/circuitcapacitychecker/mock.go

@@ -96,3 +96,6 @@ func MakeRustTrace(trace *types.BlockTrace, buffer *bytes.Buffer) unsafe.Pointer
 	goTraces[unsafe.Pointer(rustTrace)] = trace
 	return unsafe.Pointer(rustTrace)
 }
+
+func FreeRustTrace(ptr unsafe.Pointer) {
+}

rollup/pipeline/pipeline.go

@@ -368,7 +368,10 @@ func (p *Pipeline) encodeStage(traces <-chan *BlockCandidate) <-chan *BlockCandi
 				encodeTimer.UpdateSince(encodeStart)
 
 				stallStart := time.Now()
-				sendCancellable(downstreamCh, trace, p.ctx.Done())
+				if sendCancellable(downstreamCh, trace, p.ctx.Done()) {
+					// failed to send the trace downstream, free it here.
+					circuitcapacitychecker.FreeRustTrace(trace.RustTrace)
+				}
 				encodeStallTimer.UpdateSince(stallStart)
 			case <-p.ctx.Done():
 				return
@@ -395,6 +398,15 @@ func (p *Pipeline) cccStage(candidates <-chan *BlockCandidate, deadline time.Tim
 			close(resultCh)
 			deadlineTimer.Stop()
 			lifetimeTimer.UpdateSince(p.start)
+			// consume candidates and free all rust traces
+			for candidate := range candidates {
+				if candidate == nil {
+					break
+				}
+				if candidate.RustTrace != nil {
+					circuitcapacitychecker.FreeRustTrace(candidate.RustTrace)
+				}
+			}
 			p.wg.Done()
 		}()
 		for {