diff --git a/doc/go1.15.html b/doc/go1.15.html
index e2c90f5ad21ba0..597eb591c06ce1 100644
--- a/doc/go1.15.html
+++ b/doc/go1.15.html
@@ -198,6 +198,17 @@
Minor changes to the library
uint
, uint8
, uint16
, uint32
, uint64
, uintptr
,
then the value will be printed, instead of just its address.
+
+
+ On a Unix system, if the kill
command
+ or kill
system call is used to send
+ a SIGSEGV
, SIGBUS
,
+ or SIGFPE
signal to a Go program, and if the signal
+ is not being handled via
+ os/signal.Notify
,
+ the Go program will now reliably crash with a stack trace.
+ In earlier releases the behavior was unpredictable.
+
diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go
index a09ecd8e42cde4..a4d0ebfcd6cc14 100644
--- a/src/runtime/crash_cgo_test.go
+++ b/src/runtime/crash_cgo_test.go
@@ -555,3 +555,21 @@ func findTrace(text, top string) []string {
}
return nil
}
+
+func TestSegv(t *testing.T) {
+ switch runtime.GOOS {
+ case "plan9", "windows":
+ t.Skipf("no signals on %s", runtime.GOOS)
+ }
+
+ for _, test := range []string{"Segv", "SegvInCgo"} {
+ t.Run(test, func(t *testing.T) {
+ t.Parallel()
+ got := runTestProg(t, "testprogcgo", test)
+ t.Log(got)
+ if !strings.Contains(got, "SIGSEGV") {
+ t.Errorf("expected crash from signal")
+ }
+ })
+ }
+}
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index c33f88b046e81d..f5d79e561c8c1d 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -546,10 +546,10 @@ func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
if sig < uint32(len(sigtable)) {
flags = sigtable[sig].flags
}
- if flags&_SigPanic != 0 && gp.throwsplit {
+ if c.sigcode() != _SI_USER && flags&_SigPanic != 0 && gp.throwsplit {
// We can't safely sigpanic because it may grow the
// stack. Abort in the signal handler instead.
- flags = (flags &^ _SigPanic) | _SigThrow
+ flags = _SigThrow
}
if isAbortPC(c.sigpc()) {
// On many architectures, the abort function just
@@ -588,7 +588,11 @@ func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
dieFromSignal(sig)
}
- if flags&_SigThrow == 0 {
+ // _SigThrow means that we should exit now.
+ // If we get here with _SigPanic, it means that the signal
+ // was sent to us by a program (c.sigcode() == _SI_USER);
+ // in that case, if we didn't handle it in sigsend, we exit now.
+ if flags&(_SigThrow|_SigPanic) == 0 {
return
}
diff --git a/src/runtime/testdata/testprogcgo/segv.go b/src/runtime/testdata/testprogcgo/segv.go
new file mode 100644
index 00000000000000..77e75f276a5257
--- /dev/null
+++ b/src/runtime/testdata/testprogcgo/segv.go
@@ -0,0 +1,60 @@
+// Copyright 2020 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.
+
+// +build !plan9,!windows
+
+package main
+
+// static void nop() {}
+import "C"
+
+import (
+ "sync"
+ "syscall"
+)
+
+func init() {
+ register("Segv", Segv)
+ register("SegvInCgo", SegvInCgo)
+}
+
+var Sum int
+
+func Segv() {
+ c := make(chan bool)
+ var wg sync.WaitGroup
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ close(c)
+ for i := 0; i < 10000; i++ {
+ Sum += i
+ }
+ }()
+
+ <-c
+
+ syscall.Kill(syscall.Getpid(), syscall.SIGSEGV)
+
+ wg.Wait()
+}
+
+func SegvInCgo() {
+ c := make(chan bool)
+ var wg sync.WaitGroup
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ close(c)
+ for i := 0; i < 10000; i++ {
+ C.nop()
+ }
+ }()
+
+ <-c
+
+ syscall.Kill(syscall.Getpid(), syscall.SIGSEGV)
+
+ wg.Wait()
+}