[PATCH v4 04/55] selftests/mm: migration: properly cleanup fork()ed processes

[Mike Rapoport <rppt@kernel.org>]

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

Several migration test use fork() to create worker processes. These
processes are later killed, but nothing collects their exit status and they
remain as zombies in the system.

Add a helper function that kills the worker processes, waitpid()s for
them and verifies the exit status.

Replace the loops that call kill() for each process with a call to that
helper.

Reported-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 tools/testing/selftests/mm/migration.c | 47 +++++++++++++++++++-------
 1 file changed, 35 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/mm/migration.c b/tools/testing/selftests/mm/migration.c
index 16ffd3c55ee0..e504829df6b6 100644
--- a/tools/testing/selftests/mm/migration.c
+++ b/tools/testing/selftests/mm/migration.c
@@ -67,6 +67,29 @@ FIXTURE_TEARDOWN(migration)
 	free(self->pids);
 }
 
+static bool kill_children(FIXTURE_DATA(migration) * self)
+{
+	bool err = false;
+	pid_t pid;
+	int i;
+
+	for (i = 0; i < self->nthreads; i++) {
+		int status = 0;
+
+		pid = self->pids[i];
+		if (pid < 0)
+			continue;
+		if (kill(pid, SIGTERM))
+			err = true;
+		if (pid != waitpid(pid, &status, 0))
+			err = true;
+		if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGTERM)
+			err = true;
+	}
+
+	return !err;
+}
+
 int migrate(uint64_t *ptr, int n1, int n2)
 {
 	int ret, tmp;
@@ -151,7 +174,7 @@ TEST_F_TIMEOUT(migration, shared_anon, 2*RUNTIME)
 {
 	pid_t pid;
 	uint64_t *ptr;
-	int i;
+	int i, err;
 
 	ptr = mmap(NULL, TWOMEG, PROT_READ | PROT_WRITE,
 		MAP_SHARED | MAP_ANONYMOUS, -1, 0);
@@ -171,9 +194,9 @@ TEST_F_TIMEOUT(migration, shared_anon, 2*RUNTIME)
 		}
 	}
 
-	ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0);
-	for (i = 0; i < self->nthreads; i++)
-		ASSERT_EQ(kill(self->pids[i], SIGTERM), 0);
+	err = migrate(ptr, self->n1, self->n2);
+	ASSERT_EQ(kill_children(self), true);
+	ASSERT_EQ(err, 0);
 }
 
 /*
@@ -217,7 +240,7 @@ TEST_F_TIMEOUT(migration, shared_anon_thp, 2*RUNTIME)
 	uint64_t pmdsize;
 	pid_t pid;
 	uint64_t *ptr;
-	int i;
+	int i, err;
 
 	if (!thp_is_enabled())
 		SKIP(return, "Transparent Hugepages not available");
@@ -247,9 +270,9 @@ TEST_F_TIMEOUT(migration, shared_anon_thp, 2*RUNTIME)
 		}
 	}
 
-	ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0);
-	for (i = 0; i < self->nthreads; i++)
-		ASSERT_EQ(kill(self->pids[i], SIGTERM), 0);
+	err = migrate(ptr, self->n1, self->n2);
+	ASSERT_EQ(kill_children(self), true);
+	ASSERT_EQ(err, 0);
 }
 
 /*
@@ -287,7 +310,7 @@ TEST_F_TIMEOUT(migration, shared_anon_htlb, 2*RUNTIME)
 	unsigned long hugepage_size;
 	pid_t pid;
 	uint64_t *ptr;
-	int i;
+	int i, err;
 
 	hugepage_size = default_huge_page_size();
 	if (!hugepage_size)
@@ -311,9 +334,9 @@ TEST_F_TIMEOUT(migration, shared_anon_htlb, 2*RUNTIME)
 		}
 	}
 
-	ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0);
-	for (i = 0; i < self->nthreads; i++)
-		ASSERT_EQ(kill(self->pids[i], SIGTERM), 0);
+	err = migrate(ptr, self->n1, self->n2);
+	ASSERT_EQ(kill_children(self), true);
+	ASSERT_EQ(err, 0);
 }
 
 TEST_HARNESS_MAIN
-- 
2.53.0