Remove synthetic unwinder error frames from agent and instead

generate them in the unwinder with more context.

Also don't throw away frames when we can't get the process info.

If frame pointer unwinding fails still tail call interpter unwinder

luajit stack unwinding support

Works with openresty and luajit with caveats. lua_State is looked up via
uprobes on lua_pcall and lua_resume.  If uprobes aren't enabled an
attempt will be made to look up lua_State via nginx_lua_co_ctx object
which seems to work well for openresty but isn't well tested.

Fixes: parca-dev#1889

cleanup

fix lua runtime detection

[pre-commit.ci lite] apply automatic fixes

switch from L to G tracking which should be more reliable

look below rsp

make format

fix rebase issues

lua 5.10 kernel fixes

make lua unwinder work in more cases

cleanup

wip

get cur_L and jit_base from assembly

more fixes

fix instruction limits errors

cleanup

.github/workflows/test-integration-amd64.yml

@@ -102,6 +102,10 @@ jobs:
         if: ${{ always() }}
         run: GOMODCACHE=$(go env GOMODCACHE) make GO=`which go` test/integration/ruby
 
+      - name: Integration Tests (Lua)
+        if: ${{ always() }}
+        run: GOMODCACHE=$(go env GOMODCACHE) make GO=`which go` test/integration/lua
+
       - name: Integration Tests (Java)
         if: ${{ always() }}
         continue-on-error: true

.github/workflows/test-integration-arm64.yml

@@ -109,6 +109,10 @@ jobs:
         if: ${{ always() }}
         run: GOMODCACHE=$(go env GOMODCACHE) make GO=`which go` test/integration/ruby
 
+      - name: Integration Tests (Lua)
+        if: ${{ always() }}
+        run: GOMODCACHE=$(go env GOMODCACHE) make GO=`which go` test/integration/lua
+
       - name: Integration Tests (Java)
         if: ${{ always() }}
         continue-on-error: true

.gitignore

@@ -33,3 +33,5 @@ result*
 
 # java
 *.class
+
+.vscode

Dockerfile.luapre

@@ -0,0 +1,11 @@
+FROM gcr.io/distroless/static@sha256:41972110a1c1a5c0b6adb283e8aa092c43c31f7c5d79b8656fbffff2c3e61f05
+
+LABEL \
+    org.opencontainers.image.source="https://github.com/parca-dev/parca-agent" \
+    org.opencontainers.image.url="https://github.com/parca-dev/parca-agent" \
+    org.opencontainers.image.description="eBPF based always-on profiler auto-discovering targets in Kubernetes and systemd, zero code changes or restarts needed!" \
+    org.opencontainers.image.licenses="Apache-2.0"
+
+
+COPY --chown=0:0 parca-agent /bin/
+CMD ["/bin/parca-agent"]

Makefile

@@ -64,6 +64,7 @@ OUT_BPF := $(OUT_BPF_DIR)/native.bpf.o
 OUT_RBPERF := $(OUT_BPF_DIR)/rbperf.bpf.o
 OUT_PYPERF := $(OUT_BPF_DIR)/pyperf.bpf.o
 OUT_JVM := $(OUT_BPF_DIR)/jvm.bpf.o
+OUT_LUA := $(OUT_BPF_DIR)/lua.bpf.o
 OUT_BPF_CONTAINED_DIR := pkg/contained/bpf/$(ARCH)
 OUT_PID_NAMESPACE := $(OUT_BPF_CONTAINED_DIR)/pid_namespace.bpf.o
 
@@ -167,6 +168,7 @@ $(OUT_BPF): $(BPF_SRC) libbpf | $(OUT_DIR)
 	cp bpf/out/$(ARCH)/rbperf.bpf.o $(OUT_RBPERF)
 	cp bpf/out/$(ARCH)/pyperf.bpf.o $(OUT_PYPERF)
 	cp bpf/out/$(ARCH)/jvm.bpf.o $(OUT_JVM)
+	cp bpf/out/$(ARCH)/lua.bpf.o $(OUT_LUA)
 	cp bpf/out/$(ARCH)/pid_namespace.bpf.o $(OUT_PID_NAMESPACE)
 else
 $(OUT_BPF): $(DOCKER_BUILDER) | $(OUT_DIR)
@@ -248,6 +250,9 @@ test/integration/ruby: $(GO_SRC) $(LIBBPF_HEADERS) $(LIBBPF_OBJ) bpf
 test/integration/java: $(GO_SRC) $(LIBBPF_HEADERS) $(LIBBPF_OBJ) bpf
 	sudo --preserve-env=CI,C_INCLUDE_PATH,LIBRARY_PATH,PKG_CONFIG_PATH  $(GO_ENV) $(CGO_ENV) $(GO) test $(SANITIZERS) -v ./test/integration/java -count=1
 
+test/integration/lua: $(GO_SRC) $(LIBBPF_HEADERS) $(LIBBPF_OBJ) bpf
+	sudo --preserve-env=CI,C_INCLUDE_PATH,LIBRARY_PATH,PKG_CONFIG_PATH  $(GO_ENV) $(CGO_ENV) $(GO) test $(SANITIZERS) -v ./test/integration/lua -count=1
+
 .PHONY: integration-stress
 integration-stress:
 	sudo --preserve-env=CI $(GO_ENV) $(CGO_ENV) $(GO) test $(SANITIZERS) ./test/integration/... -count=5

bpf/Makefile

@@ -17,6 +17,7 @@ OUT_BPF := $(OUT_BPF_DIR)/native.bpf.o
 OUT_RBPERF := $(OUT_BPF_DIR)/rbperf.bpf.o
 OUT_PYPERF := $(OUT_BPF_DIR)/pyperf.bpf.o
 OUT_JVM := $(OUT_BPF_DIR)/jvm.bpf.o
+OUT_LUA := $(OUT_BPF_DIR)/lua.bpf.o
 OUT_PID_NAMESPACE_DETECTOR := $(OUT_BPF_DIR)/pid_namespace.bpf.o
 BPF_BUNDLE := $(OUT_DIR)/parca-agent.bpf.tar.gz
 
@@ -28,6 +29,7 @@ BPF_SRC := unwinders/native.bpf.c unwinders/go_runtime.h
 RBPERF_SRC := unwinders/rbperf.bpf.c
 PYPERF_SRC := unwinders/pyperf.bpf.c
 JVM_SRC := unwinders/jvm.bpf.c
+LUA_SRC := unwinders/lua.bpf.c
 OUT_PID_NAMESPACE_DETECTOR_SRC := pid_namespace.bpf.c
 BPF_INCLUDES := unwinders/
 
@@ -46,11 +48,11 @@ format: c/fmt
 
 .PHONY: c/fmt
 c/fmt:
-	$(CMD_CLANG_FORMAT) -i --style=file $(BPF_HEADERS) $(BPF_SRC) $(RBPERF_SRC) $(PYPERF_SRC) $(JVM_SRC) $(OUT_PID_NAMESPACE_DETECTOR_SRC)
+	$(CMD_CLANG_FORMAT) -i --style=file $(BPF_HEADERS) $(BPF_SRC) $(RBPERF_SRC) $(PYPERF_SRC) $(JVM_SRC) $(LUA_SRC) $(OUT_PID_NAMESPACE_DETECTOR_SRC)
 
 .PHONY: format-check
 format-check:
-	$(CMD_CLANG_FORMAT) --dry-run -Werror --style=file $(BPF_HEADERS) $(BPF_SRC) $(RBPERF_SRC) $(PYPERF_SRC) $(JVM_SRC) $(OUT_PID_NAMESPACE_DETECTOR_SRC)
+	$(CMD_CLANG_FORMAT) --dry-run -Werror --style=file $(BPF_HEADERS) $(BPF_SRC) $(RBPERF_SRC) $(PYPERF_SRC) $(JVM_SRC) $(LUA_SRC) $(OUT_PID_NAMESPACE_DETECTOR_SRC)
 
 # compilation options:
 BPF_CFLAGS = -Wno-address-of-packed-member \
@@ -76,7 +78,7 @@ BPF_CFLAGS = -Wno-address-of-packed-member \
 
 # tasks:
 .PHONY: clang
-clang: $(OUT_BPF) $(OUT_RBPERF) $(OUT_PYPERF) $(OUT_JVM) $(OUT_PID_NAMESPACE_DETECTOR)
+clang: $(OUT_BPF) $(OUT_RBPERF) $(OUT_PYPERF) $(OUT_JVM) $(OUT_LUA) $(OUT_PID_NAMESPACE_DETECTOR)
 
 bpf_bundle_dir := $(OUT_DIR)/parca-agent.bpf
 $(BPF_BUNDLE): $(BPF_SRC) $(LIBBPF_HEADERS)/bpf $(BPF_HEADERS)
@@ -152,3 +154,17 @@ $(OUT_JVM): $(JVM_SRC) $(LIBBPF_HEADERS) $(BPF_HEADERS) | $(OUT_DIR)
 		-O2 -emit-llvm -c -g $< -o $(@:.o=.ll)
 	$(CMD_LLC) -march=bpf -filetype=obj -o $@ $(@:.o=.ll)
 	rm $(@:.o=.ll)
+
+$(OUT_LUA): $(LUA_SRC) $(LIBBPF_HEADERS) $(BPF_HEADERS) | $(OUT_DIR)
+	mkdir -p $(OUT_BPF_DIR)
+	$(CMD_CC) -S \
+		-D__BPF_TRACING__ \
+		-D__KERNEL__ \
+		-D__TARGET_ARCH_$(SHORT_ARCH) \
+		-I $(VMLINUX_INCLUDE_PATH) \
+		-I $(LIBBPF_HEADERS) \
+		-I $(BPF_INCLUDES) \
+		$(BPF_CFLAGS) \
+		-O2 -emit-llvm -c -g $< -o $(@:.o=.ll)
+	$(CMD_LLC) -march=bpf -filetype=obj -o $@ $(@:.o=.ll)
+	rm $(@:.o=.ll)

bpf/unwinders/common.h

@@ -51,6 +51,7 @@ typedef struct {
 #define RUBY_UNWINDER_PROGRAM_ID 1
 #define PYTHON_UNWINDER_PROGRAM_ID 2
 #define JAVA_UNWINDER_PROGRAM_ID 3
+#define LUA_UNWINDER_PROGRAM_ID 4
 
 // Use ERROR_SAMPLE to report one stack frame of an error message as an interpreter symbol.
 // class -> msg provided in macro