go/test/fixedbugs/issue8047b.go
Dan Scales 7dcd343ed6 runtime: ensure that Goexit cannot be aborted by a recursive panic/recover
When we do a successful recover of a panic, we resume normal execution by
returning from the frame that had the deferred call that did the recover (after
executing any remaining deferred calls in that frame).

However, suppose we have called runtime.Goexit and there is a panic during one of the
deferred calls run by the Goexit. Further assume that there is a deferred call in
the frame of the Goexit or a parent frame that does a recover. Then the recovery
process will actually resume normal execution above the Goexit frame and hence
abort the Goexit.  We will not terminate the thread as expected, but continue
running in the frame above the Goexit.

To fix this, we explicitly create a _panic object for a Goexit call. We then
change the "abort" behavior for Goexits, but not panics. After a recovery, if the
top-level panic is actually a Goexit that is marked to be aborted, then we return
to the Goexit defer-processing loop, so that the Goexit is not actually aborted.

Actual code changes are just panic.go, runtime2.go, and funcid.go. Adjusted the
test related to the new Goexit behavior (TestRecoverBeforePanicAfterGoexit) and
added several new tests of aborted panics (whose behavior has not changed).

Fixes #29226

Change-Id: Ib13cb0074f5acc2567a28db7ca6912cfc47eecb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/200081
Run-TryBot: Dan Scales <danscales@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
2019-11-04 16:32:38 +00:00

26 lines
575 B
Go

// run
// Copyright 2014 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.
// Issue 8047. Defer setup during panic shouldn't crash for nil defer.
package main
func main() {
defer func() {
// This recover recovers the panic caused by the nil defer func
// g(). The original panic(1) was already aborted/replaced by this
// new panic, so when this recover is done, the program completes
// normally.
recover()
}()
f()
}
func f() {
var g func()
defer g()
panic(1)
}