diff --git a/misc/cgo/testsanitizers/test.bash b/misc/cgo/testsanitizers/test.bash
index 01cce956b8..9853875c7e 100755
--- a/misc/cgo/testsanitizers/test.bash
+++ b/misc/cgo/testsanitizers/test.bash
@@ -145,6 +145,7 @@ if test "$tsan" = "yes"; then
     testtsan tsan3.go
     testtsan tsan4.go
     testtsan tsan8.go
+    testtsan tsan9.go
 
     # These tests are only reliable using clang or GCC version 7 or later.
     # Otherwise runtime/cgo/libcgo.h can't tell whether TSAN is in use.
diff --git a/misc/cgo/testsanitizers/tsan9.go b/misc/cgo/testsanitizers/tsan9.go
new file mode 100644
index 0000000000..7cd0ac7dd6
--- /dev/null
+++ b/misc/cgo/testsanitizers/tsan9.go
@@ -0,0 +1,60 @@
+// Copyright 2016 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.
+
+package main
+
+// This program failed when run under the C/C++ ThreadSanitizer. The
+// TSAN library was not keeping track of whether signals should be
+// delivered on the alternate signal stack.
+
+/*
+#cgo CFLAGS: -g -fsanitize=thread
+#cgo LDFLAGS: -g -fsanitize=thread
+
+#include <stdlib.h>
+#include <sys/time.h>
+
+void spin() {
+	size_t n;
+	struct timeval tvstart, tvnow;
+	int diff;
+
+	gettimeofday(&tvstart, NULL);
+	for (n = 0; n < 1<<20; n++) {
+		free(malloc(n));
+		gettimeofday(&tvnow, NULL);
+		diff = (tvnow.tv_sec - tvstart.tv_sec) * 1000 * 1000 + (tvnow.tv_usec - tvstart.tv_usec);
+
+		// Profile frequency is 100Hz so we should definitely
+		// get a signal in 50 milliseconds.
+		if (diff > 50 * 1000) {
+			break;
+		}
+	}
+}
+*/
+import "C"
+
+import (
+	"io/ioutil"
+	"runtime/pprof"
+	"time"
+)
+
+func goSpin() {
+	start := time.Now()
+	for n := 0; n < 1<<20; n++ {
+		_ = make([]byte, n)
+		if time.Since(start) > 50*time.Millisecond {
+			break
+		}
+	}
+}
+
+func main() {
+	pprof.StartCPUProfile(ioutil.Discard)
+	go C.spin()
+	goSpin()
+	pprof.StopCPUProfile()
+}
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index 19173ac211..49c7579f27 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -212,25 +212,43 @@ func sigtrampgo(sig uint32, info *siginfo, ctx unsafe.Pointer) {
 	}
 
 	// If some non-Go code called sigaltstack, adjust.
+	setStack := false
+	var gsignalStack gsignalStack
 	sp := uintptr(unsafe.Pointer(&sig))
 	if sp < g.m.gsignal.stack.lo || sp >= g.m.gsignal.stack.hi {
-		var st stackt
-		sigaltstack(nil, &st)
-		if st.ss_flags&_SS_DISABLE != 0 {
-			setg(nil)
-			needm(0)
-			noSignalStack(sig)
-			dropm()
+		if sp >= g.m.g0.stack.lo && sp < g.m.g0.stack.hi {
+			// The signal was delivered on the g0 stack.
+			// This can happen when linked with C code
+			// using the thread sanitizer, which collects
+			// signals then delivers them itself by calling
+			// the signal handler directly when C code,
+			// including C code called via cgo, calls a
+			// TSAN-intercepted function such as malloc.
+			st := stackt{ss_size: g.m.g0.stack.hi - g.m.g0.stack.lo}
+			setSignalstackSP(&st, g.m.g0.stack.lo)
+			setGsignalStack(&st, &gsignalStack)
+			g.m.gsignal.stktopsp = getcallersp(unsafe.Pointer(&sig))
+			setStack = true
+		} else {
+			var st stackt
+			sigaltstack(nil, &st)
+			if st.ss_flags&_SS_DISABLE != 0 {
+				setg(nil)
+				needm(0)
+				noSignalStack(sig)
+				dropm()
+			}
+			stsp := uintptr(unsafe.Pointer(st.ss_sp))
+			if sp < stsp || sp >= stsp+st.ss_size {
+				setg(nil)
+				needm(0)
+				sigNotOnStack(sig)
+				dropm()
+			}
+			setGsignalStack(&st, &gsignalStack)
+			g.m.gsignal.stktopsp = getcallersp(unsafe.Pointer(&sig))
+			setStack = true
 		}
-		stsp := uintptr(unsafe.Pointer(st.ss_sp))
-		if sp < stsp || sp >= stsp+st.ss_size {
-			setg(nil)
-			needm(0)
-			sigNotOnStack(sig)
-			dropm()
-		}
-		setGsignalStack(&st)
-		g.m.gsignal.stktopsp = getcallersp(unsafe.Pointer(&sig))
 	}
 
 	setg(g.m.gsignal)
@@ -238,6 +256,9 @@ func sigtrampgo(sig uint32, info *siginfo, ctx unsafe.Pointer) {
 	c.fixsigcode(sig)
 	sighandler(sig, info, ctx, g)
 	setg(g)
+	if setStack {
+		restoreGsignalStack(&gsignalStack)
+	}
 }
 
 // sigpanic turns a synchronous signal into a run-time panic.
@@ -585,7 +606,7 @@ func minitSignalStack() {
 		signalstack(&_g_.m.gsignal.stack)
 		_g_.m.newSigstack = true
 	} else {
-		setGsignalStack(&st)
+		setGsignalStack(&st, nil)
 		_g_.m.newSigstack = false
 	}
 }
@@ -618,14 +639,32 @@ func unminitSignals() {
 	}
 }
 
+// gsignalStack saves the fields of the gsignal stack changed by
+// setGsignalStack.
+type gsignalStack struct {
+	stack       stack
+	stackguard0 uintptr
+	stackguard1 uintptr
+	stackAlloc  uintptr
+	stktopsp    uintptr
+}
+
 // setGsignalStack sets the gsignal stack of the current m to an
 // alternate signal stack returned from the sigaltstack system call.
+// It saves the old values in *old for use by restoreGsignalStack.
 // This is used when handling a signal if non-Go code has set the
 // alternate signal stack.
 //go:nosplit
 //go:nowritebarrierrec
-func setGsignalStack(st *stackt) {
+func setGsignalStack(st *stackt, old *gsignalStack) {
 	g := getg()
+	if old != nil {
+		old.stack = g.m.gsignal.stack
+		old.stackguard0 = g.m.gsignal.stackguard0
+		old.stackguard1 = g.m.gsignal.stackguard1
+		old.stackAlloc = g.m.gsignal.stackAlloc
+		old.stktopsp = g.m.gsignal.stktopsp
+	}
 	stsp := uintptr(unsafe.Pointer(st.ss_sp))
 	g.m.gsignal.stack.lo = stsp
 	g.m.gsignal.stack.hi = stsp + st.ss_size
@@ -634,6 +673,19 @@ func setGsignalStack(st *stackt) {
 	g.m.gsignal.stackAlloc = st.ss_size
 }
 
+// restoreGsignalStack restores the gsignal stack to the value it had
+// before entering the signal handler.
+//go:nosplit
+//go:nowritebarrierrec
+func restoreGsignalStack(st *gsignalStack) {
+	gp := getg().m.gsignal
+	gp.stack = st.stack
+	gp.stackguard0 = st.stackguard0
+	gp.stackguard1 = st.stackguard1
+	gp.stackAlloc = st.stackAlloc
+	gp.stktopsp = st.stktopsp
+}
+
 // signalstack sets the current thread's alternate signal stack to s.
 //go:nosplit
 func signalstack(s *stack) {