[dev.regabi] all: merge master (1d78139) into dev.regabi

Merge List:

+ 2020-12-26 1d78139128 runtime/cgo: fix Android build with NDK 22
+ 2020-12-25 2018b68a65 net/mail: don't use MDT in test
+ 2020-12-23 b116404444 runtime: shift timeHistogram buckets and allow negative durations
+ 2020-12-23 8db7e2fecd runtime: fix allocs-by-size and frees-by-size buckets
+ 2020-12-23 fb96f07e1a runtime: fix nStackRoots comment about stack roots
+ 2020-12-23 d1502b3c72 lib/time, time/tzdata: update tzdata to 2020e
+ 2020-12-23 30c99cbb7a cmd/go: add the Retract field to 'go help mod edit' definition of the GoMod struct
+ 2020-12-23 49d0b239cb doc: fix a typo in contribute.html
+ 2020-12-23 98a73030b0 cmd/go: in 'go get', promote named implicit dependencies to explicit
+ 2020-12-23 fd6ba1c8a2 os/signal: fix a deadlock with syscall.AllThreadsSyscall() use
+ 2020-12-23 b0b0d98283 runtime: linux iscgo support for not blocking nptl signals
+ 2020-12-22 223331fc0c cmd/go/internal/modload: add hint for missing implicit dependency

Change-Id: I76d79f17c546cab03fab1facc36cc3f834d9d126

1 files changed, 13 insertions, 0 deletions

diff --git a/src/syscall/syscall_linux_test.go b/src/syscall/syscall_linux_test.go
index 153d0efef1..adeb7c9ebb 100644
--- a/src/syscall/syscall_linux_test.go
+++ b/src/syscall/syscall_linux_test.go
@@ -597,6 +597,14 @@ func compareStatus(filter, expect string) error {
 	return nil
 }
 
+// killAThread locks the goroutine to an OS thread and exits; this
+// causes an OS thread to terminate.
+func killAThread(c <-chan struct{}) {
+	runtime.LockOSThread()
+	<-c
+	return
+}
+
 // TestSetuidEtc performs tests on all of the wrapped system calls
 // that mirror to the 9 glibc syscalls with POSIX semantics. The test
 // here is considered authoritative and should compile and run
@@ -647,6 +655,11 @@ func TestSetuidEtc(t *testing.T) {
 	}
 
 	for i, v := range vs {
+		// Generate some thread churn as we execute the tests.
+		c := make(chan struct{})
+		go killAThread(c)
+		close(c)
+
 		if err := v.fn(); err != nil {
 			t.Errorf("[%d] %q failed: %v", i, v.call, err)
 			continue