qemu/0035-tests-test-thread-pool-is-racy-add-.patch

From: Bruce Rogers <brogers@suse.com>
Date: Fri, 13 Apr 2018 11:46:47 -0600
Subject: tests: test-thread-pool is racy - add some barriers

I imagine there is more to be done to fix the memory consistency
races here, but these added barriers at least let it pass on ppc64le,
whereas before it would fail regularly there.

[BR: minor edits to pass qemu's checkpatch script]
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 tests/test-thread-pool.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/test-thread-pool.c b/tests/test-thread-pool.c
index 9cdccb3a47..2cbabaadd3 100644
--- a/tests/test-thread-pool.c
+++ b/tests/test-thread-pool.c
@@ -171,6 +171,7 @@ static void do_test_cancel(bool sync)
     /* Cancel the jobs that haven't been started yet.  */
     num_canceled = 0;
     for (i = 0; i < 100; i++) {
+        smp_mb(); /* test is currently racy */
         if (atomic_cmpxchg(&data[i].n, 0, 3) == 0) {
             data[i].ret = -ECANCELED;
             if (sync) {
@@ -185,6 +186,7 @@ static void do_test_cancel(bool sync)
     g_assert_cmpint(num_canceled, <, 100);
 
     for (i = 0; i < 100; i++) {
+        smp_mb(); /* test is currently racy */
         if (data[i].aiocb && data[i].n != 3) {
             if (sync) {
                 /* Canceling the others will be a blocking operation.  */
@@ -201,6 +203,7 @@ static void do_test_cancel(bool sync)
     }
     g_assert_cmpint(active, ==, 0);
     for (i = 0; i < 100; i++) {
+        smp_mb(); /* test is currently racy */
         if (data[i].n == 3) {
             g_assert_cmpint(data[i].ret, ==, -ECANCELED);
             g_assert(data[i].aiocb == NULL);