diff options
author | Ian Lance Taylor <iant@golang.org> | 2020-04-18 20:11:46 -0700 |
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committer | Ian Lance Taylor <iant@golang.org> | 2020-04-22 00:01:14 +0000 |
commit | e5bd6e1c7944713c816cf94ae412a700c271cfca (patch) | |
tree | 2fd972e8b6e0e72379e5a6adc626e034416efa9d | |
parent | 5a75f7c0b0789fe04ea4879a524cc95dbe734636 (diff) | |
download | go-e5bd6e1c7944713c816cf94ae412a700c271cfca.tar.gz go-e5bd6e1c7944713c816cf94ae412a700c271cfca.zip |
runtime: crash on SI_USER SigPanic signal
Clean up the code a little bit to make it clearer:
Don't check throwsplit for a SI_USER signal.
If throwsplit is set for a SigPanic signal, always throw;
discard any other flags.
Fixes #36420
Change-Id: Ic9dcd1108603d241f71c040504dfdc6e528f9767
Reviewed-on: https://go-review.googlesource.com/c/go/+/228900
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
-rw-r--r-- | doc/go1.15.html | 11 | ||||
-rw-r--r-- | src/runtime/crash_cgo_test.go | 18 | ||||
-rw-r--r-- | src/runtime/signal_unix.go | 10 | ||||
-rw-r--r-- | src/runtime/testdata/testprogcgo/segv.go | 60 |
4 files changed, 96 insertions, 3 deletions
diff --git a/doc/go1.15.html b/doc/go1.15.html index e2c90f5ad2..597eb591c0 100644 --- a/doc/go1.15.html +++ b/doc/go1.15.html @@ -198,6 +198,17 @@ TODO <code>uint</code>, <code>uint8</code>, <code>uint16</code>, <code>uint32</code>, <code>uint64</code>, <code>uintptr</code>, then the value will be printed, instead of just its address. </p> + + <p><!-- CL --> + On a Unix system, if the <code>kill</code> command + or <code>kill</code> system call is used to send + a <code>SIGSEGV</code>, <code>SIGBUS</code>, + or <code>SIGFPE</code> signal to a Go program, and if the signal + is not being handled via + <a href="/pkg/os/signal/#Notify"><code>os/signal.Notify</code></a>, + the Go program will now reliably crash with a stack trace. + In earlier releases the behavior was unpredictable. + </p> </dd> </dl> diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go index a09ecd8e42..a4d0ebfcd6 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 c33f88b046..f5d79e561c 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 0000000000..77e75f276a --- /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() +} |