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go/misc/cgo/test/testdata/issue9400_linux.go
Paul E. Murphy 682435dd99 misc/cgo/test: reduce likeliness of hang in Test9400
If a GC triggers while spinning in RewindAndSetgid, it may result in
this test hanging. Avoid it by disabling the collector before entering
the uninterruptable ASM conditional wait.

Fixes #49695

Change-Id: Ie0a03653481fb746f862469361b7840f4bfa8b67
Reviewed-on: https://go-review.googlesource.com/c/go/+/365836
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2021-11-30 15:28:46 +00:00

64 lines
1.5 KiB
Go

// 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.
// Test that SIGSETXID runs on signal stack, since it's likely to
// overflow if it runs on the Go stack.
package cgotest
/*
#include <sys/types.h>
#include <unistd.h>
*/
import "C"
import (
"runtime"
"runtime/debug"
"sync/atomic"
"testing"
"cgotest/issue9400"
)
func test9400(t *testing.T) {
// We synchronize through a shared variable, so we need two procs
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
// Start signaller
atomic.StoreInt32(&issue9400.Baton, 0)
go func() {
// Wait for RewindAndSetgid
for atomic.LoadInt32(&issue9400.Baton) == 0 {
runtime.Gosched()
}
// Broadcast SIGSETXID
runtime.LockOSThread()
C.setgid(0)
// Indicate that signalling is done
atomic.StoreInt32(&issue9400.Baton, 0)
}()
// Grow the stack and put down a test pattern
const pattern = 0x123456789abcdef
var big [1024]uint64 // len must match assembly
for i := range big {
big[i] = pattern
}
// Disable GC for the duration of the test.
// This avoids a potential GC deadlock when spinning in uninterruptable ASM below #49695.
defer debug.SetGCPercent(debug.SetGCPercent(-1))
// Temporarily rewind the stack and trigger SIGSETXID
issue9400.RewindAndSetgid()
// Check test pattern
for i := range big {
if big[i] != pattern {
t.Fatalf("entry %d of test pattern is wrong; %#x != %#x", i, big[i], uint64(pattern))
}
}
}