From a89768461f20fc66f28420cc49df9ce765cf8253 Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Fri, 4 Sep 2015 10:58:42 -0700 Subject: [release-branch.go1.5] runtime: unblock special glibc signals on each thread Glibc uses some special signals for special thread operations. These signals will be used in programs that use cgo and invoke certain glibc functions, such as setgid. In order for this to work, these signals need to not be masked by any thread. Before this change, they were being masked by programs that used os/signal.Notify, because it carefully masks all non-thread-specific signals in all threads so that a dedicated thread will collect and report those signals (see ensureSigM in signal1_unix.go). This change adds the two glibc special signals to the set of signals that are unmasked in each thread. Fixes #12498. Change-Id: I797d71a099a2169c186f024185d44a2e1972d4ad Reviewed-on: https://go-review.googlesource.com/14297 Reviewed-by: David Crawshaw Reviewed-on: https://go-review.googlesource.com/16967 Run-TryBot: Austin Clements Reviewed-by: Ian Lance Taylor Reviewed-by: Russ Cox --- misc/cgo/test/setgid_linux.go | 19 ++++++++++++++++++- src/runtime/signal_linux.go | 4 ++-- 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/misc/cgo/test/setgid_linux.go b/misc/cgo/test/setgid_linux.go index 197f01fb7e..ca95e08359 100644 --- a/misc/cgo/test/setgid_linux.go +++ b/misc/cgo/test/setgid_linux.go @@ -14,11 +14,14 @@ package cgotest import "C" import ( + "os" + "os/signal" + "syscall" "testing" "time" ) -func testSetgid(t *testing.T) { +func runTestSetgid() bool { c := make(chan bool) go func() { C.setgid(0) @@ -26,7 +29,21 @@ func testSetgid(t *testing.T) { }() select { case <-c: + return true case <-time.After(5 * time.Second): + return false + } + +} + +func testSetgid(t *testing.T) { + if !runTestSetgid() { t.Error("setgid hung") } + + // Now try it again after using signal.Notify. + signal.Notify(make(chan os.Signal, 1), syscall.SIGINT) + if !runTestSetgid() { + t.Error("setgid hung after signal.Notify") + } } diff --git a/src/runtime/signal_linux.go b/src/runtime/signal_linux.go index 2f25b59663..2cc76b2415 100644 --- a/src/runtime/signal_linux.go +++ b/src/runtime/signal_linux.go @@ -44,8 +44,8 @@ var sigtable = [...]sigTabT{ /* 29 */ {_SigNotify, "SIGIO: i/o now possible"}, /* 30 */ {_SigNotify, "SIGPWR: power failure restart"}, /* 31 */ {_SigNotify, "SIGSYS: bad system call"}, - /* 32 */ {_SigSetStack, "signal 32"}, /* SIGCANCEL; see issue 6997 */ - /* 33 */ {_SigSetStack, "signal 33"}, /* SIGSETXID; see issue 3871, 9400 */ + /* 32 */ {_SigSetStack + _SigUnblock, "signal 32"}, /* SIGCANCEL; see issue 6997 */ + /* 33 */ {_SigSetStack + _SigUnblock, "signal 33"}, /* SIGSETXID; see issues 3871, 9400, 12498 */ /* 34 */ {_SigNotify, "signal 34"}, /* 35 */ {_SigNotify, "signal 35"}, /* 36 */ {_SigNotify, "signal 36"}, -- cgit v1.2.3-54-g00ecf