PR 6850

Fix handling of fork with uretprobe_instances outstanding.
Add regression test.

1 files changed, 87 insertions, 0 deletions

diff --git a/testsuite/systemtap.base/bz6850.c b/testsuite/systemtap.base/bz6850.c
new file mode 100644
index 00000000..a8b78110
--- /dev/null
+++ b/testsuite/systemtap.base/bz6850.c
@@ -0,0 +1,87 @@
+/* Regression test for bugzilla 6850 */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#define PASS_MARKER "./bz6850_pass"
+
+/* All this in an attempt to defeat gcc's over-aggressive inlining... */
+typedef pid_t (*forker)(int);
+static forker call_chain[];
+
+/*
+ * Both parent and child return from fork2() and fork1().  Both
+ * processes will hit the uretprobe trampolines.  The handlers should
+ * run in the parent.  With the bug fix in place, the child will return
+ * correctly and do the exec (but won't run the handlers).
+ */
+static pid_t fork2(int ignored)
+{
+	return fork();
+}
+
+static pid_t fork1(int func_index)
+{
+	++func_index;
+	return call_chain[func_index](func_index);	/* fork2() */
+}
+
+static pid_t fork_and_exec2(int func_index)
+{
+	pid_t child;
+	++func_index;
+	child = call_chain[func_index](func_index);	/* fork1() */
+	if (child == 0) {
+		/* I'm the child.  Create the marker file.  */
+		char *child_args[] = { "/bin/touch", PASS_MARKER, NULL };
+		char *child_env[] = { NULL };
+		execve(child_args[0], child_args, child_env);
+		perror("execve");
+		fprintf(stderr, "FAIL: child couldn't exec.\n");
+		exit(2);
+	}
+	return child;
+}
+
+static pid_t fork_and_exec1(int func_index)
+{
+	++func_index;
+	return call_chain[func_index](func_index);	/* fork_and_exec2() */
+}
+
+static forker call_chain[] = {
+	fork_and_exec1,
+	fork_and_exec2,
+	fork1,
+	fork2,
+	NULL
+};
+
+main()
+{
+	pid_t child, wait_child;
+	int status = 0;
+
+	(void) unlink(PASS_MARKER);
+	child = call_chain[0](0);	/* fork_and_exec1() */
+	if (child < 0) {
+		fprintf(stderr, "FAIL: fork_and_exec1() failed.\n");
+		exit(1);
+	}
+	wait_child = wait(&status);
+	if (wait_child != child) {
+		fprintf(stderr, "FAIL: waited for %d but got %d\n",
+						child, wait_child);
+		exit(1);
+	}
+	if (WEXITSTATUS(status) != 0) {
+		fprintf(stderr, "FAIL: child died with status = %d\n",
+			WEXITSTATUS(status));
+		exit(1);
+	}
+	exit(0);
+}