1 files changed, 22 insertions, 0 deletions
diff --git a/libbacktrace/backtrace_test.c b/libbacktrace/backtrace_test.c
index 34d3519..6155c9b 100644
--- a/libbacktrace/backtrace_test.c
+++ b/libbacktrace/backtrace_test.c
@@ -22,6 +22,7 @@
 #include <signal.h>
 #include <sys/ptrace.h>
 #include <sys/wait.h>
+#include <errno.h>
 #include <unistd.h>
 #include <inttypes.h>
 
@@ -29,6 +30,8 @@
 
 #define FINISH(pid) dump_frames(&backtrace); if (pid < 0) exit(1); else return false;
 
+#define WAIT_INTERVAL_USECS   1000
+
 // Prototypes for functions in the test library.
 int test_level_one(int, int, int, int, bool (*)(pid_t));
 
@@ -52,6 +55,21 @@ void dump_frames(const backtrace_t* backtrace) {
   }
 }
 
+void wait_for_stop(pid_t pid, size_t max_usecs_to_wait) {
+  siginfo_t si;
+  size_t usecs_waited = 0;
+
+  while (ptrace(PTRACE_GETSIGINFO, pid, 0, &si) < 0 && (errno == EINTR || errno == ESRCH)) {
+    if (usecs_waited >= max_usecs_to_wait) {
+      printf("The process did not get to a stopping point in %zu usecs.\n",
+             usecs_waited);
+      break;
+    }
+    usleep(WAIT_INTERVAL_USECS);
+    usecs_waited += WAIT_INTERVAL_USECS;
+  }
+}
+
 bool check_frame(const backtrace_t* backtrace, size_t frame_num,
                  const char* expected_name) {
   if (backtrace->frames[frame_num].proc_name == NULL) {
@@ -153,6 +171,10 @@ void verify_proc_test(pid_t pid, bool (*verify_func)(pid_t)) {
     kill(pid, SIGKILL);
     exit(1);
   }
+
+  // Wait up to 1 second for the process to get to a point that we can trace it.
+  wait_for_stop(pid, 1000000);
+
   bool pass = verify_func(pid);
   if (ptrace(PTRACE_DETACH, pid, 0, 0) != 0) {
     printf("Failed to detach from pid %d\n", pid);