From e9ff1e84081f89f24e27edc9dcfad12c43e51ec3 Mon Sep 17 00:00:00 2001
From: "Dmitry V. Levin" <ldv@altlinux.org>
Date: Tue, 9 Jul 2019 19:27:58 +0000
Subject: [PATCH] tests: robustify strace -k tests against link-time optimizer

Some distributions enable by default a link-time optimizer that
mangles stack_fcall sample executables in a way that renders them
unusable for test purposes.

Robustify tests to defeat link-time optimizer.

* tests/stack-fcall.h (f0, f1, f2, f3): Add second parameter.
* tests/stack-fcall.c (main): Pass main as the second parameter to f0.
* tests/stack-fcall-0.c (f0): Add second parameter f, pass the xor of it
and f0 to f1.
* tests/stack-fcall-1.c (f1): Add second parameter f, pass the xor of it
and f1 to f2.
* tests/stack-fcall-2.c (f2): Add second parameter f, pass the xor of it
and f2 to f3.
* tests/stack-fcall-3.c: Include <asm/unistd.h>.
(f3): Add second parameter f, invoke __NR_gettid syscall with the xor
of f and f3 as its argument.
---
 tests/stack-fcall-0.c | 4 ++--
 tests/stack-fcall-1.c | 4 ++--
 tests/stack-fcall-2.c | 4 ++--
 tests/stack-fcall-3.c | 4 +++-
 tests/stack-fcall.c   | 4 ++--
 tests/stack-fcall.h   | 8 ++++----
 6 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/tests/stack-fcall-0.c b/tests/stack-fcall-0.c
index 8a26a79c..e334df1c 100644
--- a/tests/stack-fcall-0.c
+++ b/tests/stack-fcall-0.c
@@ -7,7 +7,7 @@
 
 #include "stack-fcall.h"
 
-int f0(int i)
+int f0(int i, unsigned long f)
 {
-	return f1(i) - i;
+	return f1(i, f ^ (unsigned long) (void *) f0) - i;
 }
diff --git a/tests/stack-fcall-1.c b/tests/stack-fcall-1.c
index b5cd89b3..96888ef0 100644
--- a/tests/stack-fcall-1.c
+++ b/tests/stack-fcall-1.c
@@ -7,7 +7,7 @@
 
 #include "stack-fcall.h"
 
-int f1(int i)
+int f1(int i, unsigned long f)
 {
-	return f2(i) + i;
+	return f2(i, f ^ (unsigned long) (void *) f1) + i;
 }
diff --git a/tests/stack-fcall-2.c b/tests/stack-fcall-2.c
index 16beee58..9386f4ab 100644
--- a/tests/stack-fcall-2.c
+++ b/tests/stack-fcall-2.c
@@ -7,7 +7,7 @@
 
 #include "stack-fcall.h"
 
-int f2(int i)
+int f2(int i, unsigned long f)
 {
-	return f3(i) - i;
+	return f3(i, f ^ (unsigned long) (void *) f2) - i;
 }
diff --git a/tests/stack-fcall-3.c b/tests/stack-fcall-3.c
index 538b6565..d027e326 100644
--- a/tests/stack-fcall-3.c
+++ b/tests/stack-fcall-3.c
@@ -7,11 +7,13 @@
 
 #include <signal.h>
 #include <unistd.h>
+#include <asm/unistd.h>
 
 #include "stack-fcall.h"
 
-int f3(int i)
+int f3(int i, unsigned long f)
 {
+	syscall(__NR_gettid, f ^ (unsigned long) (void *) f3);
 	switch (i) {
 	case 1:
 		return kill(getpid(), SIGURG);
diff --git a/tests/stack-fcall.c b/tests/stack-fcall.c
index cf4000e5..bc970b24 100644
--- a/tests/stack-fcall.c
+++ b/tests/stack-fcall.c
@@ -9,7 +9,7 @@
 
 int main(void)
 {
-	f0(0);
-	f0(1);
+	f0(0, (unsigned long) (void *) main);
+	f0(1, (unsigned long) (void *) main);
 	return 0;
 }
diff --git a/tests/stack-fcall.h b/tests/stack-fcall.h
index cca0f94f..881fca28 100644
--- a/tests/stack-fcall.h
+++ b/tests/stack-fcall.h
@@ -14,7 +14,7 @@
 
 #endif
 
-int f0(int i);
-int f1(int i);
-int f2(int i);
-int f3(int i);
+int f0(int i, unsigned long);
+int f1(int i, unsigned long);
+int f2(int i, unsigned long);
+int f3(int i, unsigned long);
-- 
2.40.0