4 files changed, 42 insertions, 0 deletions
diff --git a/executor/common.h b/executor/common.h
index 2ee0d5bd2..fb7b04f4a 100644
--- a/executor/common.h
+++ b/executor/common.h
@@ -668,6 +668,9 @@ static void loop(void)
 #if SYZ_HAVE_SETUP_TEST
 			setup_test();
 #endif
+#if SYZ_HAVE_SETUP_EXT_TEST
+			setup_ext_test();
+#endif
 #if GOOS_akaros
 #if SYZ_EXECUTOR
 			dup2(child_pipe[0], kInPipeFd);
diff --git a/executor/common_ext.h b/executor/common_ext.h
index 22361649f..edbfcac0b 100644
--- a/executor/common_ext.h
+++ b/executor/common_ext.h
@@ -9,3 +9,6 @@
 
 // This file can also define SYZ_HAVE_SETUP_EXT to 1 and provide
 // void setup_ext() function that will be called during VM setup.
+
+// This file can also define SYZ_HAVE_SETUP_EXT_TEST to 1 and provide
+// void setup_ext_test() function that will be called during setup of each test process.
diff --git a/executor/common_ext_example.h b/executor/common_ext_example.h
index 0299b6d4f..0cabcb75c 100644
--- a/executor/common_ext_example.h
+++ b/executor/common_ext_example.h
@@ -8,3 +8,10 @@ static void setup_ext()
 {
 	debug("example setup_ext called\n");
 }
+
+#define SYZ_HAVE_SETUP_EXT_TEST 1
+static void setup_ext_test()
+{
+	// See TestCommonExt.
+	*(uint64*)(SYZ_DATA_OFFSET + 0x1234) = 0xbadc0ffee;
+}
diff --git a/executor/common_ext_test.go b/executor/common_ext_test.go
index 45ba3a3cf..2815b095a 100644
--- a/executor/common_ext_test.go
+++ b/executor/common_ext_test.go
@@ -10,6 +10,8 @@ import (
 	"time"
 
 	"github.com/google/syzkaller/pkg/csource"
+	"github.com/google/syzkaller/pkg/ipc"
+	"github.com/google/syzkaller/pkg/ipc/ipcconfig"
 	"github.com/google/syzkaller/pkg/osutil"
 	"github.com/google/syzkaller/prog"
 )
@@ -31,4 +33,31 @@ func TestCommonExt(t *testing.T) {
 	if !bytes.Contains(out, []byte("example setup_ext called")) {
 		t.Fatalf("setup_ext wasn't called:\n%s", out)
 	}
+
+	// The example setup_ext_test does:
+	// *(uint64*)(SYZ_DATA_OFFSET + 0x1234) = 0xbadc0ffee;
+	// The following program tests that that value is present at 0x1234.
+	test := `syz_compare(&(0x7f0000001234)="", 0x8, &(0x7f0000000000)=@blob="eeffc0ad0b000000", AUTO)`
+	p, err := target.Deserialize([]byte(test), prog.Strict)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cfg, opts, err := ipcconfig.Default(target)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cfg.Executor = bin
+	cfg.Flags |= ipc.FlagDebug
+	env, err := ipc.MakeEnv(cfg, 0)
+	if err != nil {
+		t.Fatalf("failed to create env: %v", err)
+	}
+	defer env.Close()
+	_, info, _, err := env.Exec(opts, p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if call := info.Calls[0]; (call.Flags&ipc.CallFinished) == 0 || call.Errno != 0 {
+		t.Fatalf("bad call result: flags=%x errno=%v", call.Flags, call.Errno)
+	}
 }