runtime: fix cgo signals detection
CL 64070 removed lockOSThread from the cgocall path, but didn't update
the signal-in-cgo detection in sighandler. As a result, signals that
arrive during a cgo call are treated like they arrived during Go
execution, breaking the traceback.
Update the cgo detection to fix the backtrace.
Fixes #47522
Change-Id: I61d77ba6465f55e3e6187246d79675ba8467ec23
Reviewed-on: https://go-review.googlesource.com/c/go/+/339989
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go
index ce7bed9..9df6fcd 100644
--- a/src/runtime/crash_cgo_test.go
+++ b/src/runtime/crash_cgo_test.go
@@ -536,6 +536,29 @@
}
}
+func TestCgoPanicCallback(t *testing.T) {
+ t.Parallel()
+ got := runTestProg(t, "testprogcgo", "PanicCallback")
+ t.Log(got)
+ want := "panic: runtime error: invalid memory address or nil pointer dereference"
+ if !strings.Contains(got, want) {
+ t.Errorf("did not see %q in output", want)
+ }
+ want = "panic_callback"
+ if !strings.Contains(got, want) {
+ t.Errorf("did not see %q in output", want)
+ }
+ want = "PanicCallback"
+ if !strings.Contains(got, want) {
+ t.Errorf("did not see %q in output", want)
+ }
+ // No runtime errors like "runtime: unexpected return pc".
+ nowant := "runtime: "
+ if strings.Contains(got, nowant) {
+ t.Errorf("did not see %q in output", want)
+ }
+}
+
// Test that C code called via cgo can use large Windows thread stacks
// and call back in to Go without crashing. See issue #20975.
//
@@ -603,6 +626,28 @@
}
}
+func TestAbortInCgo(t *testing.T) {
+ switch runtime.GOOS {
+ case "plan9", "windows":
+ // N.B. On Windows, C abort() causes the program to exit
+ // without going through the runtime at all.
+ t.Skipf("no signals on %s", runtime.GOOS)
+ }
+
+ t.Parallel()
+ got := runTestProg(t, "testprogcgo", "Abort")
+ t.Log(got)
+ want := "SIGABRT"
+ if !strings.Contains(got, want) {
+ t.Errorf("did not see %q in output", want)
+ }
+ // No runtime errors like "runtime: unknown pc".
+ nowant := "runtime: "
+ if strings.Contains(got, nowant) {
+ t.Errorf("did not see %q in output", want)
+ }
+}
+
// TestEINTR tests that we handle EINTR correctly.
// See issue #20400 and friends.
func TestEINTR(t *testing.T) {
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index 07f371c..8854629 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -688,9 +688,11 @@
}
print("PC=", hex(c.sigpc()), " m=", _g_.m.id, " sigcode=", c.sigcode(), "\n")
- if _g_.m.lockedg != 0 && _g_.m.ncgo > 0 && gp == _g_.m.g0 {
+ if _g_.m.incgo && gp == _g_.m.g0 && _g_.m.curg != nil {
print("signal arrived during cgo execution\n")
- gp = _g_.m.lockedg.ptr()
+ // Switch to curg so that we get a traceback of the Go code
+ // leading up to the cgocall, which switched from curg to g0.
+ gp = _g_.m.curg
}
if sig == _SIGILL || sig == _SIGFPE {
// It would be nice to know how long the instruction is.
diff --git a/src/runtime/signal_windows.go b/src/runtime/signal_windows.go
index 3fe352e..16c36d0 100644
--- a/src/runtime/signal_windows.go
+++ b/src/runtime/signal_windows.go
@@ -218,11 +218,11 @@
print("Exception ", hex(info.exceptioncode), " ", hex(info.exceptioninformation[0]), " ", hex(info.exceptioninformation[1]), " ", hex(r.ip()), "\n")
print("PC=", hex(r.ip()), "\n")
- if _g_.m.lockedg != 0 && _g_.m.ncgo > 0 && gp == _g_.m.g0 {
+ if _g_.m.incgo && gp == _g_.m.g0 && _g_.m.curg != nil {
if iscgo {
print("signal arrived during external code execution\n")
}
- gp = _g_.m.lockedg.ptr()
+ gp = _g_.m.curg
}
print("\n")
diff --git a/src/runtime/testdata/testprogcgo/panic.go b/src/runtime/testdata/testprogcgo/panic.go
new file mode 100644
index 0000000..4ddef3a
--- /dev/null
+++ b/src/runtime/testdata/testprogcgo/panic.go
@@ -0,0 +1,29 @@
+package main
+
+import "C"
+
+// This program will crash.
+// We want to test unwinding from a cgo callback.
+
+/*
+void panic_callback();
+
+static void call_callback(void) {
+ panic_callback();
+}
+*/
+import "C"
+
+func init() {
+ register("PanicCallback", PanicCallback)
+}
+
+//export panic_callback
+func panic_callback() {
+ var i *int
+ *i = 42
+}
+
+func PanicCallback() {
+ C.call_callback()
+}
diff --git a/src/runtime/testdata/testprogcgo/sigthrow.go b/src/runtime/testdata/testprogcgo/sigthrow.go
new file mode 100644
index 0000000..665e3b0
--- /dev/null
+++ b/src/runtime/testdata/testprogcgo/sigthrow.go
@@ -0,0 +1,20 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// This program will abort.
+
+/*
+#include <stdlib.h>
+*/
+import "C"
+
+func init() {
+ register("Abort", Abort)
+}
+
+func Abort() {
+ C.abort()
+}
