From 7c22af830a72adf30b18ee3d1744aab8e3c009a8 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Tue, 16 Feb 2016 14:42:24 -0500 Subject: [PATCH] runtime: fix deadlock in TestCrashDumpsAllThreads TestCrashDumpsAllThreads carefully sets the number of Ps to one greater than the number of non-preemptible loops it starts so that the main goroutine can continue to run (necessary because of #10958). However, if GC starts, it can take over that one spare P and lock up the system while waiting for the non-preemptible loops, causing the test to eventually time out. This deadlock is easily reproducible if you run the runtime test with GOGC=1. Fix this by forcing GOGC=off when running this test. Change-Id: Ifb22da5ce33f9a61700a326ea92fcf4b049721d1 Reviewed-on: https://go-review.googlesource.com/19516 Run-TryBot: Austin Clements TryBot-Result: Gobot Gobot Reviewed-by: Russ Cox --- src/runtime/crash_unix_test.go | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/src/runtime/crash_unix_test.go b/src/runtime/crash_unix_test.go index 1a012eb6ef..771b303f6e 100644 --- a/src/runtime/crash_unix_test.go +++ b/src/runtime/crash_unix_test.go @@ -14,6 +14,7 @@ import ( "os/exec" "path/filepath" "runtime" + "strings" "syscall" "testing" ) @@ -52,6 +53,18 @@ func TestCrashDumpsAllThreads(t *testing.T) { cmd = exec.Command(filepath.Join(dir, "a.exe")) cmd = testEnv(cmd) cmd.Env = append(cmd.Env, "GOTRACEBACK=crash") + + // Set GOGC=off. Because of golang.org/issue/10958, the tight + // loops in the test program are not preemptible. If GC kicks + // in, it may lock up and prevent main from saying it's ready. + newEnv := []string{} + for _, s := range cmd.Env { + if !strings.HasPrefix(s, "GOGC=") { + newEnv = append(newEnv, s) + } + } + cmd.Env = append(newEnv, "GOGC=off") + var outbuf bytes.Buffer cmd.Stdout = &outbuf cmd.Stderr = &outbuf -- 2.50.0