Fix proc test flakiness

Thread from earlier test can show up in `/proc/self/tasks` while the
thread tears down. Account for that when searching for procs for the
first time in the test.

PiperOrigin-RevId: 361689673

1 files changed, 13 insertions, 10 deletions

diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc
index e508ce27f..61a421788 100644
--- a/test/syscalls/linux/proc.cc
+++ b/test/syscalls/linux/proc.cc
@@ -2162,7 +2162,13 @@ class BlockingChild {
     return tid_;
   }
 
-  void Join() { Stop(); }
+  void Join() {
+    {
+      absl::MutexLock ml(&mu_);
+      stop_ = true;
+    }
+    thread_.Join();
+  }
 
  private:
   void Start() {
@@ -2172,11 +2178,6 @@ class BlockingChild {
     mu_.Await(absl::Condition(&stop_));
   }
 
-  void Stop() {
-    absl::MutexLock ml(&mu_);
-    stop_ = true;
-  }
-
   mutable absl::Mutex mu_;
   bool stop_ ABSL_GUARDED_BY(mu_) = false;
   pid_t tid_;
@@ -2190,16 +2191,18 @@ class BlockingChild {
 TEST(ProcTask, NewThreadAppears) {
   auto initial = ASSERT_NO_ERRNO_AND_VALUE(ListDir("/proc/self/task", false));
   BlockingChild child1;
-  EXPECT_NO_ERRNO(DirContainsExactly("/proc/self/task",
-                                     TaskFiles(initial, {child1.Tid()})));
+  // Use Eventually* in case a proc from ealier test is still tearing down.
+  EXPECT_NO_ERRNO(EventuallyDirContainsExactly(
+      "/proc/self/task", TaskFiles(initial, {child1.Tid()})));
 }
 
 TEST(ProcTask, KilledThreadsDisappear) {
   auto initial = ASSERT_NO_ERRNO_AND_VALUE(ListDir("/proc/self/task/", false));
 
   BlockingChild child1;
-  EXPECT_NO_ERRNO(DirContainsExactly("/proc/self/task",
-                                     TaskFiles(initial, {child1.Tid()})));
+  // Use Eventually* in case a proc from ealier test is still tearing down.
+  EXPECT_NO_ERRNO(EventuallyDirContainsExactly(
+      "/proc/self/task", TaskFiles(initial, {child1.Tid()})));
 
   // Stat child1's task file. Regression test for b/32097707.
   struct stat statbuf;